Is there an "all the above"?
While I certainly love the flexibility of two man sets, I more enjoy being flexible in the sets you can deploy with the same personnel. Haynesworth is tall enough to play on the tackle in the 34, explosive enough to play on the guard in the 43. The 34 OLB's can play with their hand in the dirt. Offensive personnel dictates "base" defense and you have three possibilities to morph into. 34 two gap alignment, 43 over or under, all 52 derivatives, all do different things. Offense checks, you check. Suddenly the offense is put on the defensive. Miscommunication in blocking schemes, uncertainty over interior routes, timeout burned. The enemy is on their heels and you've yet to fire a round. Eloquent in it's lethality.
Extend this further to sub. Same sub personnel with a two man line of 92 and 75, and suddenly you have the 42, the 33, and the 24 all at your disposal. All can do different things without declaring through personnel. Compound this with two shutdown corners and a stable of good safeties, and you can literally do anything inside. It's not about 43 or 34, it's about the multiskers they have acquired to run either. The ambiguity and flexibility of a certain set is nice, but having the ability to seamlessly morph between several increases that advantage exponentially. The stuff Belichick will be able to do this year is going to be incredible.