They took the old blocking stance and replace it. It's not a skill anymore as to when you did it you skilled up shield(though I thought it was cool). Now it's all based on block rate and abilities to block (through stats like DEX, VIT and MND). It's very RPG and random now and we can't directly control when we can block(only influence the frequency of it with glad abilities).

I still thought it was very RPG-like to decide to either use shield or sword while in combat but SE still took it out with the over-haul of the system(which really sucks IMO). That wouldn't made PLD a much better shield and support healer to draw in hate and defense while constantly having his/her shield up and ready! Pugilist also had a defense stance(though I never saw it) and I thought would of been very useful.