These are just some suggestions for each tallent:

BERSERKER:
I feel that once you get below 25% health it won't take much more than 1 hit to kill you off, so depending on where you fall (which percentage so below 10 or between 16-20) sort of becomes pure luck. I think once you hit a certain percentage like 15% or 10% you damage is simply doubled OR
once you get below 50% you do 125% damage, 25% health = 150% damage and 10% = 200% damage
Something slightly more manageable that a tiny difference of 5%.

COUNTER STRIKE:
Tbh it's rare enough to dodge in the first place but then to only have a 25% chance to counter attack, let me tell you that's never gonna happen... Maybe this should also increase your dodging % or make the counter attack a 75%.

Also I didn't know you could block attacks with your shield, I thought it just increased your physical and magical armour.

I haven't read any of the comments (too many of them) so I have no idea if you've added any ideas or not. Hope this helps tho.