Synergies.

[whyBish]

I don't.
Skills with sharp dimishing returns are akin to one point wonders, and those are broken to me.
What's the point of having 20 skill ranks if no one in their right mind is going to use them ?

I like the idea of diminishing skills, but not *sharp* diminishing skills. Adding points should give something, but maybe not as much as the first five-10 points. Diminishing returns also make balancing much easier than linear returns, especially with the offensive skills.

As to the second part, I would say that the passive tree for the zon is the almost perfect example. No-one would think of maxing Dodge or evade or avoid et. al. but they can custom invest to their own preference without feeling like they need to plonk in 20 points. This reduces 'one trick ponies' syndrome that is essentially forced on certain characters such as the sorc (e.g. she pretty much is forced into 20/20 skill mastery which means two useful skills to use at ~level 80)