Our 2 year old had a great time at both parks in March. I think there is enough to do to make it worth it, as long as you and the others want to go. Don't JUST go for the 2 year old, but don't stay away on the 2 year old's behalf either.
Undeniably, WDW parks have more to offer that age group, especially MK. We went to Universal after a week at WDW. If we had to make a choice, WDW would win. But doing both is the best!
At IOA, our 2 year old loved Seuss Landing, which had 4 attractions for little ones, Camp Jurassic, Me Ship the Olive, and Storm Force Accelatron. At Universal Studios, he loved Shrek 4D, Animal Planet Live, A Day in the Park with Barney (and playground outside the theatre "Barney's Bak Yard"), E.T. Adventure, Curious George Goes to Town. At both parks we spent a good amount of time just enjoying walking around and greeting characters. He also enjoyed Mythos at IOA.
Have fun!