Both of these classes have excellent self healing and I imagine that's more the problem then damage.
I love the Bloodthirst tree and it was built to give Berserkers more survivability which it does, I just think it probably does this a little to well (especially now that +healing effects regen).
I've heard similar things from cursed though I haven't really played one enough to know first hand but it's been mentioned on IRC a number of times that at higher levels they're practically unkillable. Or things like, oh my cursed loves brittle oozes because it's more life to drain etc.
Without looking at the talent trees I'd put a cap on how many creatures some of the cursed abilities can effect. If your draining hit points from every creature in you gloom well that's to much and it encourages things like not shutting down the portals in the end fight since it's free life regen. Maybe Gloom should only effect TL targets like Body of Fire, Corona, and Thunderstorm. But like I said, I didn't really look at the trees so I might be talking out my...
Also we should nerf jumpgate ala the thread yura posted awhile back
(edit) With damage going down the self-healing abilities got an indirect buff too. Which is something to keep in mind. I don't remember what beta that happened in but in theory Berserkers and Cursed should be having an even easier time since that beta.