Uhm, I have to call a botch on this. In an actiongame the options you have during a fight is essential to keep me entertained, while repetition is best avoided. The more different forms of attack or things you can do, the more strategic options you have in a fight, the better the game play usually is. Dungeon Siege 3 for example gave me fingertip access to 11 actions along with powered up versions, Diablo 3 gives me 6 different attacks, Dead Island gave me two roles (Xian, damagedealer and medic) with many different actions (rage, jumpkick, headstomp, backstab).
In Borderlands 2 you have enough skillpoints to fill one of your skilltrees, in Borderlands (and Dead Island) you filled two. This means that when people specialize (and they will) their character will become one of 3 cookie-cutters who can do 1 action over and over again. That's going to be old and repetitive quickly and we are going to see much less diversity overall.
In Borderlands 1 you would combine 2 trees and filled up two different roles based on your choice. My Mordecai was a Sniper, specialized in using his bird and half decent with a pistol even if I sacrificed the gunslinger tree. If I play Zero (the assassin) in Borderlands 2 I will only be a sniper. The total amount of actions available to me in a fight is hide, aim and shoot.