A slightly more Pratchettian Therianthrope (PEACH)

[DracoDei]

Ability scores: I'm actually trying to reduce the therianthropes combat power, your suggestion would make it a tad too close to the WotC version for my taste.

Yeah, different goals...

Giants: I've checked out the giants and their racial HD, and don't think I need to change how therianthrope animal HD works. Also: troll therianthrope. regeneration 5/fire, silver or therianthope. Fire trolls are even worse. ;P

Is that really how Regeneration stacks?
Personally I would call it Regeneration 5 that effects all damage not by fire or acid and the acid damage is reduced to non-lethal damage that is NOT subject to the Regeneration 5 healing... Of course in the worst case this means you have 3 different types of damage to worry about, rather than just 2, but we all know I prefer precision to total simplicity usually...