Favored Enemy Shapechanger revisited

[I love cats]

So given that there are very few lycanthropes in the module and it makes IG sense for a ranger to be devoted to "hunting changelings"  in the form of shapechanger.  I would suggest that to reflect this they get immunity to the most annoying druid spells in the module of Entangle and  Spike Growth, or some other manner of bonuses clearly marked towards the druid class.