I don't think I'd like the right-side action buttons moved down. I'm ok with what they did since I don't really expect many games to fully exploit "dual-analog" anyway. In fact I don't expect very many games to offer more than just enhanced features for N3DS ... gotta keep that compatibility with the original model. There will be some N3Ds exclusive games, but not many "A" titles will be. The right-side 'nub' will probably end up functioning like the Gamecube "C-stick" did, i.e. camera position mostly or only occasional actions. So altering the position of the action buttons for the sake of a full-sized slidepad would've been a waste and would've just made the thing more awkward to play on.
They should've just gone full blown with a new system - it's been long enough. But I'm definitely going to buy a N3DS XL. I'm still playing on a launch model 3DS and I've waited long enough to upgrade.