Have you guys considered implementing a combat system similar to salem's? I know it's certainly not perfect, but I feel like with enough polishing a system like that could become something interesting. I just think that perhaps the issue with all current combat systems is that regardless of what extra additions you "cling" on to them (namely defence/offence bars, cards, etc), they always end up boiling down to attacking and defending until either combatant screws up or loses due to being outstatted or outnumbered.
There's also the issue from the development side of things that it could become increasingly difficult (dare I say exponentially so) to implement new moves/attacks and give people a reason to use them at all without simply making them OP and therefore rendering all other previous attacks/defences useless (or making combat so unnecessarily complicated that not many people will have the patience to learn the tree of attacks they should use against each particular situation). Like I said, in the end all current combat boils down to is breaking someone's defence by spamming the OP attacks and keeping yourself alive by spamming the OP defences, regardless of how many moves there are to choose from.
I think in that regard salem's combat system allows for more flexibility by doing away with any defending/attacking, and instead turning the combat into a game of strategically using the right moves at the right times to land a hit on an opponent, and relying on character movement to dodge incoming attacks. (for the people that don't know, in salem the only way to block an attack is to actually move and dodge it, there's no defence moves or anything of the sort, so it ends up being a game of skillfully dodging people and outsmarting them, rather than spamming defences to render all opponent attacks useless. There's also stuns, dashes, dodge moves and whatnot). So in that sense one could (theoretically) add as many different combat moves as necessary, since the combat isn't so heavily reliant on numbers, and rather requires players to be mechanically and strategically skilled in order to win fights.
Just to illustrate a bit, here are a couple of videos that summarize the way I see salem vs haven combat (bias/rudeness not intended, I'm just trying to express my view of both systems)
Haven:
https://www.youtube.com/watch?v=Fzavftr0Bz4Salem:
https://youtu.be/Hm25hssGPzM?t=48s To clarify a bit, the monster being fought in this video is easily able to knock even the highest statted characters out if you mess up at the wrong time (even in one hit in this particular case), this person manages to kill it with a relatively low-statted character due to being very experienced at the system. Pvp works very similarly to this. Again, it's not a game of numbers, but rather of being skilled at the game and taking advantage of your opponent's weakness (which is just a relatively dumb monster in this case, but I'm sure you get the point).
I also think this is one of the things people loved so much about the legacy haven combat system (movmant kambertz and whatnot), in that you could easily take out a much stronger character if they moved at the wrong time, and you weren't instantly screwed just because they had better numbers and spammed abilities better than you.
Now, I'm sure you guys (the devs) are by now growing a bit tired of working on the same combat stuff, but I'm just dropping this post here as a suggestion incase you ever decide to give combat another swing, maybe it could even lead to an even better result.