I think that's a misconception due to Wade's hybrid 3-4, and we do have the bigger nose tackles, and I don't think you're getting any bigger with a 4-3 front anyway. Traditionally, in 3-4 Donald is a DE, and in 4-3 he's your DT, and in a hybrid it's really not much different because almost everyone is playing one gap anyway.
But the 4-3 tackles are typically smaller and faster than 3-4 ends. So our problem stopping the run was really more to do with size and gap responsibility in Wade's hybrid 3-4.
I think it's all about where you want Donald to play, because I think he can be a total nightmare from 3T or 5T. Also, SJD proved this season that he is more than adequate at 1T and 0T with Gaines providing solid competition and possible 3T as well.
Even Wade's 3-4 under was successful stopping the run when the right players were out there, but he was playing wack a mole with prioritizing the run/pass, and I think a lot of that was due to the secondary.