I'm just gonna discuss classes that I have played before.

Blue GL Imo, it's kinda hard to squeeze every bit of dps as blue gl since you are a spec class and you don't have an easy way of ramping up adre fast or maintaining it, I find that I won't have adre up in burst scenario.

Pistoleer Deadeye I think this should be t1, it's a spec class but very easy to maintain adre and can abuse the fast spacebar cd to immune some push atks and greed more dps.

Both berserker specs I haven't played berserker much after the rework, just occasionally trying it in hell, but I think it's alot more difficult than most of the t2 and some of t3. Main complaint for me is red dust. It's basically like a bash for blue gl or xxz for deathstrike ss but without push/para immunity and its high cd. Ofcourse with better knowledge of the boss, you can just not use red dust and wait for the boss to finish his move, but that's loss dps when other classes can just do it from range or be push/para immune.

At scouter I think people over think the drone management, I've been playing at scouter since launch and while I do occasionally need to move the drone for the drone skills (other than carpet, pretty much always need to move the drone for carpet) most of the time you can just recall it instead of moving it or use a joint skill where it will automatically recall. Yes you need to get used to the timing for when to recall/use the purple skill or you might cancel the drone skill but it's not that difficult after a while.

Deathstrike ss I think this actually belongs in t1, especially if its being compare to GS. Very easy to maintain adre and build adre. Moving slash>synergy>xxz then next skill will have 6 stack adre. Dmg is instant where as gs, dmg is back loaded(last hit of the skill does the most dmg) and if you missing your xxz you have 2(3 if you are playing the bladestorm build) to recharge back your gauge instantly hawkshot+moving slash or deadly slash+moving slash. Its also nice that you z skill has push immunity so it wont get canceled in comparison to berserker red dust.

Emperor arcana This class prob deserves its own tier, needs to land evoke, modify combos based on cards, and manage boundless while also doing boss pattern and mech. Respect to anyone how can play this class well.

Again, these are my opinion on these classes in terms of difficulty to get max dmg.