The problem with the concentration checks is you're using 3.5 DCs, but not giving characters the skills they're supposed to have factored in. They should have 4 skill ranks +1 per level added in, so not having this is a large negative and so it's near impossible for them to actually hit the DCs to successfully concentrate.
The "break free" action just using flat strength also makes it difficult to make the check, and again near impossible for casters. But this one might be actually following the rules unlike concentration, I'll have to check. But a near the start of the game web having DC17 is RIDICULOUS. What caster can even dream of hitting DC17 to break free? (and they have no choice b/c they can't make their concentration check to cast while in web due to no skill ranks)
There should at least be an option for high STR fighters to "Break a friend free", or apply a torch to burn it off.
