1. Sneak attack does increase as you level up. The tooltip doesn't change but look at the formula they're using to calculate it in the combat log (bottom right). It includes level. I have my own reservations as to HOW they're calculating it, but it DOES increase per level.
2. Use off-hand weapon = extra damage. If you get the dual wielder feat & use rapiers you can have 3d8 + 3xDEX modifier + sneak attack damage per turn with a Thief. That easily outclasses most classes especially when you consider it's an infinite resource.
3. Agreed completely on expertise but that will presumably be added in future patches
4. I haven't made my mind up yet on the jump/disengage conundrum. I'd prefer to see it taken out because, primarily, it allows for too much mobility and avoiding of attacks of opportunity
