I've been playing 1.6.x for a week. I liked the new stuff, sprinting is better (in SP, but I heard it's broken in MP), but boats became incredibly hard to control. Now they work like horses: you make turns only if the boat is moving by pressing W and looking. If you want to stop, you need to turn yourself 180º, press W and pray for the boat not to crash (letting it to crash is less painful, in my opinion) . I tried to repair a bridge by using a boat. I gave up, better off floating on the river or scaffolding.