I recently posted a categorization of my and some other builds on the discord. I figured i should explain a bit but it got lengthy so i repost it here with some more explanations:
Best single dam:
S+(potentially overpowered 4k+ Cata 1 damage): CCM Marksman, Arc Legion Evo, Engi (Harpers on Drone/Tactical) -new addition
S (2k+): BM SoJ or SoR, Shield Throw Guard, Engi Nanos/Infernous or similar, Multishot MM
A (1k+): BM Sword throw+SoJ, All single dam Evos other than Arc Legion, Ele Sumo Warper, Sniper MM (under Camo)
B (700-1k): Onhit Gunguard, Onhit Gunvoker, Sumvoker, SFX MM, Striker Engi, Aoe focused Evoker, Melee Sumo (with butterfly)
C (~500): Vanya/Novagun/Prayer Guard, Infernous Gunvoker
D (better use ignite): Nader MM
Disclaimer damage values are only based on my builds and what i saw on video. Dont roast me because your Sumo or Sword thrower does 2k damage 
Best AOE (quickness, mobs hit per skilluse, userate, area covered, cleartime, how good at clearing Catas/Australia):
S: Nader, Aoe Evoker, Novagun Guard, Sword throw BM with Global Grinder
A: Army Sumo Carnagor, BM Onslaught/SoR With Global weapon, Shield Throw Guard Global Shield, Onhit Guard/Evo,
B: Sumvoker, MM Withering Tube (sfx centered), Striker Engi, general Evo, Melee Sumo, Engi Nanos/spider/infernous
C: Standard SoJ/SoR BM with Global weapon/Faraday, general MM Marksman
D: Sniper
Most Fun (fun, skills in use, variability, content able to do, satisfying moves, feel)
S: Onslaught/SoR BM
A: Novagun/Vanya/Prayer Guard, Melee Sumo, Sword throw/SoJ BM, Engi Nanos/Spider/infernous
B: Bone/SC Evo (used to be S tier), Multishot MM, Onhit GunGuard/Evo, Shield Throw Guard, Nader
C: Withering Tube/SFX MM, Summoners, Standard damage maxed SoR/SoJ, most evos, Striker Engi
D: Sniper
I’m gonna expand a bit on the “most fun” category since it is subjective and cant be discussed based on numbers. I initially had some of the A-tier in the S-Tier aswell but i realized the difference is too high to keep that up. For me one of the most important things is how satisfying playing a char is, how does it feel to shred mobs. And that can be dependant on as little a thing as a good impact sound. I remember when i first loaded Diablo 3 and the first Char was Monk and the first ever hit i did just made me kinda feel the punch. I guess it was a combo of animation and sound that gave the illusion but it was kindof an aha moment that you can achieve this. The Onslaught/SoR BM has alot of means to create these moments.
It is not a complicated build SoR,SoA,Charge,PoR, Zeal and the most important thing Onslaught (near) max, the rest into surges. It therefore has 4 main attack skills the two from the red tree and the two from the yellow tree - that is already a good amount to handle but not too much. But also these 4 skills can be combined situationally to create very satisfying combos it is not just more of the same shit like with alot of evo skills. There is allways a best way to combine them for maximum damage while maintaining speed. It has 2 quickly availabe movement skills which which alone puts him in a unique position. And those movement skills (Charge and PoR) are different and also the best in the category of all classes thx to the passive Onslaught. They both are buffed heavily in damage and most importantly range. Having charge on a 25m range makes it available to nearly everything on the screen. Without the range extension it feels frustrating when you want to use it but cant. It is also the only movement skill that can teleport you a terrain level up or down which is super fun on its own. PoR on the other hand can be a monster AOE skill when combined with the right sword. It provides one the biggest damage for an aoe skill and it has a low cooldown. Then we have SoR which is kindof a quick slam and SoA which is a big slam. And they both feel like slamming. SoA could be visually better but when you zoom around and end your streak on a champion and then do the final slam and oneshot it with SoA and turn around everything is dead it gives you that Matrix Neo feeling, i would describe it.
So this build is so action Jackson when you combine all the movement and impacting damage skills but after a while becomes super fluid thx to the quick availability and combinability of the skills. And you have nearly infinite level of control of stepping on the gas pedal or taking it easy. It is insane how you can zoom through map while still doing something.
And besides that that build also does very good single and aoe damage, so it performs really good. It is also not extreme in equipment needs. So there is that.
The other char i had in there was the Spell Curse Bone Evoker but since the nerf of SC due to its one shotting Bosses via armor break it fell down quite a bit . Not because it couldnt do the oneshot boss thing anymore (it still can btw) but it lost its splash which made it usefull and impacting when clearing eg Catas. It used to create alot of these wow moments where you press a button and then instantly havoc breaks out and again the sound plays a big role - those chain explosions are just nice. To create those moments there had to be alot of set up like positioning, getting off the curse without dying and then triggering them rightly. But yeah one shotting Myth Bosses was a bit over the top. But again that wasnt the appeal of the build in the first place just an unlucky side effect.
Novagun/Vanya/Prayer is a late addition to the A-List. People allways say novaguns are dumb and i agree that while levelling they are kinda dumb because the game doesnt challenge you hard in enough in that phase. But later, that is not the case anymore and you need more than just the guns to do the more challenging levels and you need very good ones too. First of all again those guns, especially the phase novaguns just have a good look,sound and feel. To me the best in the game. Everyone remember the video of Hellgate when the Templar was surrounded by a horde of zombies and waited for the Nova to go off. Thats what you get.
And then when they start to fall off a bit in damage in the later levels Prayers come in nicely and provide for a nice situational finnisher. Smite has not the best sound but the animation is cool and the feel is nice when you jump in a very big horde do Retribution, fire off your guns and when you realize oh shit thats not enough you go anchor, do the fist in the air and everything gets finnished off - thats just cool and fun. Its also cool that the long cd on weapons and skills makes you anchor just for singular triggers. You dont sit for ages in anchor you just use it for a one of barrage and then move on. And also this build has more to do than people think. You get hit alot because you want to get swamped, so you have to actively manage your health via skills alot since you cant escape. Due to the cooldowns of anchor and smite you need to evaluate the situation a bit and decide when to trigger what for the best possible combo and when your decision was right it feels good - thats one of the most important things for good gamplay. It is actually one of the chars where i consume more mana pots than i collect which is a good sign for me. It is a bit low on single damage thats where Vanyas come in to get you a little bit of an edge there but its not a boss killer. On the other hand it is the easiest and one of the most effective Luck Farmers in the game due to the availability of Trakts which makes a quick switch to a luck build easy and it doesnt compromise on playstyle. And since it got Taunts it automatically makes it a top tier aoe build.
Melee sumo just rose into A tier because of the newly found way to do good single damage via wall butterflying. That was allways the problem with the build when it simply took too long to kill bosses. Melee sumo is cool because the spin you create with Dark Offering is again a reallly nicely executed and good feeling skill similar to the novas just thats it is kinda more ninja. It combines a bit of spell casting with melee which is rare. It has quite a few options to play around with aswell with curses and its tanky as fuck also one of my quickest chars. It has its downsides like the finnicky butterfly or the not so super effectfull spells but it just reached a list for me. It is one of my goto treasure passageway hunters in Catas.
Sword throw BM became A-List when i realized that i needed to scrap the idea of doing ONLY sword throwing and add in Soj for Boss kills AND i combined in a bit of the yellow movement tree to get onslaught to a mid level. Now that is the Char with the most different options at any given time. It has 5 very different options to do damage. Throw a sword when at range or the mobs line up perfectly, Sword Typhoon for some heavy aoe on spread out mobs, charge to single out one mob, PoR to massive aoe to your near surroundings while getting out or just slice away with SoJ in case the mobs are too tanky. I love the combo of throwing a sword and instantly charge behind it. Sword Typhoon is a massive aoe skill with splash swords and gives you that finnisher feel when you charge in on the Champion, kill him with SoJ and before his minions swamp you you kill them off with Typhoon. The number of cool combos on this char is crazy. I still dont like him as much as the Onslaught SoR BM because hee feels lighter, more spread out and struggles with Mana at times (Bosses can be a bitch with Sojes mana consumption).
Engi, what can i say, is just a cool char with so much stuff to do and equip. He doesnt have this one impact thing (spiders and crashes get near though) but he is very solid and nice to play, very balanced (except for tactical mode in combination with some freak non faction guns). Alot of situational skills - not just blow out everything you got. You gotta love Engi.
Notable mentions: Multishot feels just nice. Its a dumb skill but what can i say, hitting that button does feel satisfying. Nader, blowing out all nades while the strike ticks and then with a boom the whole screen dies, very cool. Onhit Guard, i remember when the Flagship devs discussed a nerf to onhits and were kindof asking why the fuck people defend onhits so much when it just provides screen clutter. But yeah thats the appeal and i like it, the disco novas going off and killing randomly remote targets on the horizon is just nice.
Please discuss, i dont mind if you heavily disagree, i need input for new builds or adjustmends and variations.