Class changes would be nice, but one thing I've seen a lot of other games do and would like to see in Ffxiv is they break up attacks into smaller parts.
So for example if a tank buster hits for 21K, instead of 1 21k hit, it would be broken up into 3 7k hits. The outgoing damage is the and but if would be a buff to parry and block. Parry isn't used because it isn't reliable (plus it scales terribly) but with this you'd have three chances for parry to work as apposed to one. You sort of see that with holy blade dance but it would be nice to see more attacks work that way.