I'll bring up the issue of call lightning working indoors.
One thing you must remember is the druid spellset is horribly nerfed in NWN vs PnP, moreso than any other casting class.
Having played 4 druids far into epic levels on several servers, call lightning is as it is because quite frankly, call lightning is the only spell they have to kill things. And that isn't an exaggeration in the least. Wizards on the other hand can kill you fifteen different ways til Sunday, with or without firebrand.
With the alterations to summons and animal companions RL already has in place, I wouldn't start a druid unless I was bribed honestly. Altering call lightning in any way and I doubt anyone ever would (can't really recall many druids in RL as it is, for obvious reasons). What do you expect a druid to do if they can't cast it indoors? Sit there and watch everyone else participate in killing? Restrict themselves to wandering around outside killing worgs forever (since that's all they're going to be able to kill)?
For a class that has little going for it, I really hope you don't take away the only thing it does have to use. Especially when the other casting peers it has are still horribly overpowered and too versatile in this ruleset. Removing or altering call lightning from what it is makes Harper Scouts more useful looking than druids would be. Logic is nice to have, but it shouldn't trump balance.