make it a permanent choice. a free feat at that level and lock it in.
Also, I can't tell if you're being facetious. But I find your comment comical.
Half and half. Druids have complex lore that gives them interesting narrative levers to pull on, but are also saddled with a lot of responsibilities as a result; aversion to metal armour, oaths of varying sorts, moral obligations, etc. It can be difficult playing that straight when many others don't, even moreso when your limited toolset is sabotaged.
It's no more disruptive than a monk's level 20, or drd and pm's progressively growing ocr. All the other forms grow in size and power as the druid does, why wouldn't these?
Level 20 Monk capstone, Dragon Disciple and Pale Master's OCR are all symptomatic of their growth as characters, true. But unlike Druids, these are
involuntary. I've checked D&D editions 2 through 5, and all of them are very specific; you
choose the form your shape takes. There's nothing involuntary about the specific appearance, shape or characteristics of the shape you've chosen. While this is not entirely reasonable to accurately 1:1 recreate on NWN, such as adding 50+ animal forms, it is most certainly possible to allow players to choose whether they become an animal that can reasonably be assumed to be just that, or to go HAM.
Aren't there mundane animal shapes they can take if they want to play furry friend?
Yes, but those have their own issues also. There's a slew of character concepts that don't align with playing an urban druid. Hamstringing the capability of players to pursue varied options in character portrayal ultimately lessens the narrative availability on offer. Also, anecdotally, a lot of those forms suffer a lot of scrutiny because of the unfortunate frequency of other Druids using them; Garda make it a point to punt rabbits when they see them, just in case, if not trying to put arrows in them for a rabbit stew. If someone wants to pick something innocuous and also unlikely to be attacked, such as a crow or raven, that's more or less impossble past 12 since your raven form becomes something out of nightmares.