1. They should scale with strength for bashing, that was a classlead change a few rounds ago. I don't know how well it scales, though. The PvP strength scaling isn't fantastic, but that doesn't mean anything about PvE scaling.
2. Feasible, probably. May not really be worth it, though, depending on how well it scales with strength. Constitution is probably going to be the better choice right now.
3. They don't really have anything great that contributes to group bashing that isn't just their middle of the road damage, so... average, I guess?
4. Depthswalker is a candidate for being targetted as a high priority, but it really depends on the specific groups involved. They have lots of group utility (including room hinder), high damage potential, and aeon.