So I've been an active player since launch despite all the connection problems and after trying every class getting to know each ones strengths, weaknesses etc. it's slightly obvious which classes are considered overpowered. The classes that fall into this category in my opinion are Warlord, Conqueror and Warden. I would also mention Peacekeeper but I only struggle with their AoE the rest of their kit is OK to deal with but again this is just my own opinion.
My reasoning is pretty simple.

1) Because every dam night these are pretty much the only 3 characters I come up against.

2) Last night alone I faced 9 different players in a row ALL playing warden. It takes the fun out of the game playing against the same class over and over. Yes they have few effective/fast moves like top light and aoe (which if blocked you get a free GB I know) plus the vortex but if against a high level player (tourney players like Extheleon) it's almost impossible to beat them unless you play warden, warlord or conq. I'm by no means a great player, I have a 65% W/L ratio on my main which is Kensei. But on my warlord I have an 80% W/L ratio and I'll be the first to admit I'm pretty poor with warlord! Also bear in mind I only played like 20 games on warlord.

3) Speak of the devil, Warlord has pretty much every tool you need. Uninterruptable heavies, quick lights & aoe, solid blocking and finally, the turtle destroyer headbutt. I'm certain this class in particular will be getting a nerf pretty soon out of the 3.

4) Conqueror is just the safest class in the game. If played by a "skilful" player they will never get parried or caught in a mixup because they just need to turtle and shield bash followed by light and repeat... Peacekeeper and Warlord I know are decent counters and can open them up quite well.

Again I want to stress this is just my opinion and I'm sure I'm wrong in many peoples eyes. I know people hate facing shugoki because of their armour and 1 hit kill potential. Others struggle with the speed of the Peacekeeper. Most of my opinion is based on playing with Kensei and watching tournaments/streamers etc. Hearing 90% of them all saying Conq, Warlord, Warden are Top Tier along with Peacekeeper and possibly Shugoki kinda speaks for itself. I don't think a raider, beserker, kensei, or lawbringer has gotten further than last 16 of any tournament so far. Again I could be wrong but I guess that's what a forum is for.

Let me know what you guys think.