This cuts both ways though. If the party is in the “Valley of Aberrations”, they will likely be surprised when the DM brings in the CR 6 refluffed druid to dispel LTH.
Well sure, if the encounter makes no sense and is REALLY there just to mess with the party (as in to specifically counter one of their tactics just because the DM wants too)? That's bad. And any spell that "requires" the DM to consistently have to find silly ways around it? Needs a good look, or at the very least needs to be addressed.
And to be clear, Tiny Hut is annoying BUT then either:
1. Ban or house rule it; or
2. Roll with it and respond in "realistic" and hopefully fun ways. Tiny hut doesn't protect animals (pack, companions, whatever) and the like, for example. Tiny hut also doesn't change the length of time required to rest and that can have serious (and not the least bit unanticipated) consequences.