I lowed DAoC combo system - think if you evolved on that, you could make a really nice combat system,
As I recall it DAoC had tab targeting - which I am also a big fan of - but if you make it action based, and combo - the combo's would be even hardrt to complete, thus creating a bigger advantage for the "better" player
Active block and parry of course - again with follow up combo-possibilities
Also playing Shroud of the Avatar at the moment, and their DECK system is actually pretty cool once you get used to it
The extra nice thing with the deck system. is that it is not possible to have an optimal rotation, since you never know what is available for you - don’t care if it’s a deck system, but something that pushes players away from "the optimal rotation" would be nice
Shroud of the Avatar, also have the possibilities to stack attacks, 2-3 of the same attacks to one more powerful version - or mix 2 attacks into a new "better" one - kind of a combo you could say - which I also think is a nice thought