Homebrew/alternate setting and optimization?

[Belial_the_Leveler]

1) Assume nonstandard DnD setting. I.e. it doesn't have the standard cosmology, and any planes that do exist aren't the same as those described in the SRD. A simple example of that would be a case where every plane or part of a plane is some deific/cosmic guy's domain and they've messed with the rules in it.

2) Assume homebrew creatures only. The DM has changed the various creatures to fit the setting and also be less exploitable. I.e. a dragon's scales are thick enough to negate touch and ranged touch attacks and prolonged contact with a dragon can be highly corruptive, ala Smaug in the Hobbit.




Any optimization advice for the setting?