I would move Archery from decent to OP. It is difficult at lower levels, but once you get a decent bow you can clear a room and nothing will even touch you. Also, I'd recommend picking up Illusion if you are gonna go dual dagger assassin, because it has alot of CC which can get you out of those hairy situations and when you get the silent casting you can turn your enemies against each other and pick off the remaining ones. As for sneak at 100 there is a perk at 100 that makes it to where if you stealth, enemies begin to search for you again and they lose track of you. Illusion can also come in handy with this, because you can invis and stealth and they will completely lose you, so you can rethink and go back in for an assassination or two. Dual daggers can be fun if you like taking your time, but you have to play alot more carefully and as I said, I believe Illusion is a must.