Yeah, I think one of the problems with games like God of War is that they ARE pure button mashers. Ninja Gaiden is the only action game I can think of where combat was really really skill based. You absolutely HAD to master every one of Ryu's moves to make it through that game--and it was HARD--but extremely satisfying when you did it.
If Assassin's Creed could just lean a little more in that direction then I think it'd have a great balance of strategy/reflex in the combat. As it is now though, it really feels too formulaic and repetitive. It's like, "oh, here's a normal enemy--hold block, hit counter, insta-kill." "Oh, here's a shielded enemy, sheath weapon, hit disarm, insta-kill." And those are basically the only variations on it. In Brotherhood, they essentially replaced disarm with the kick move, which does the same thing basically, except that you have to hit one more button afterwards to do the insta-kill. I don't get the argument that it takes much thought. Sure, it's not a button-masher, but at least in button-mashers like God of War, you actually occasionally have to dodge, block, roll, jump, etc. You don't have to do anything of the sort in Assassin's Creed. Every combat scenario is always the same, one of the two variations above--wash, rinse, repeat.