Personally, I'd prefer a seperate dagger skill altogether, it just doesn't make sense to have them tossed into the same category as other one-handed weapons. Whether either solution (entirely new skill tree or added perks) is viable is something we'll see after the editor gets released.
Having all the one-handed weapons just lumped together has never made sense. They've been doing it (sort of) since Oblivion though. Long swords and short swords balance completely differently, and are weighted against different eventualities. Long swords are generally balanced toward the point where as short swords are balanced to the hilt. Axes are a completely different animal altogether, as well as maces. I was a little disappointed that they took the dumbed down way and stuck with that instead of having individual weapon type or style skill trees with synergy bonuses to the other related skill trees. i.e. a master of long sword gets a 20% bonus to his short sword skills because they are somewhat similar. Same between axes and maces etc.
However, I live with the largely lumped generalization of"one-handed" and "two-handed". Pretty soon, there's just going to be three trees for the console kiddies: Weapons, stealth and magic.
Kind of disappointed with the loss of Birthsigns and attributes too.