Id say it's a good thing. I don't play WoW currently but I may come back (as I usually do at the start of an xpac) but I did used to tank and got through Normal modes through SoO. The one really annoying thing I always found was the start of the next raid was just annoying. I gained barely anymore avoidance for it to make a difference (say, 25% to 28%) and it still was me using active mitigations for major boss mechanics.
Making people use their abilities (like H Paladins with their Bulwark, DK's using their shields correctly, etc etc) is what made tanking fun. Not me going "LOL AVOIDANCE CAP" in Cata.