More advanced battle system please!

[Nutz]

Your first question is simple. Combat was purposely not designed that way because it's overly intricate and any latency greater than 100 ms or so would completely destroy it. When you're playing an MMO you're essentially streaming a game (at least parts of it) so when you want to parry a mob's attack, you'd have to hit the timing right, then the server would check it, then the server would send confirmation that it was right and the reaction would occur. This can happen quickly enough under ideal conditions, but any small hiccup would lead to missing blocks and parries frequently when it looked like it should have gone through. To combat this they'd have to make it more lenient, but then people would almost never miss them. It's better to have them occur based on math because it's easier to do, fair, and allows you to do things other than try to block/parry every single attack.

As to the second part. Well in team based combat what else would you expect? Healers heal, tanks tank, etc. If players weren't reliant on each other then why bother making group content? If they made all player characters more powerful to not rely on each other so much, but then made the fights harder to balance it out we'd be right back in the same spot but with bigger numbers (note that this actually is happening anyway).

EDIT: as to skill chain type combat mechanics: they were in v1.0 but eventually removed because they didn't work well. They worked on it a while but eventually decided not to re-implement them because they felt it was too much to do during combat. Given the pace of combat I think I agree, though perhaps they could create chains based on off-GCD skills that various classes have. Creating a combo between various classes' regular weapon skills (as it used to be, but combat was much slower) would do nothing more than sometimes create chains at random because people wouldn't be able to coordinate such things. Doing something like Howling Fist -> Dragonfire Dive = [some cool effect with additional damage] might be cool to have and add another layer to combat, but I haven't heard that they're considering anything like this.