As a player:
The DM was getting frustrated with his battles ending too quickly, so he banned the Banishment spell outright. No discussion, no forewarning...we were in the middle of combat and he flatly refused to allow the spell. "I'm tired of you guys instantly defeating my monsters!" He then told us to remove the spell from our character sheets, and replace it with something else. So I replaced it with Polymorph.
As a DM who have felt the pain of you DM, but not to the point of banning a spell mid combat, I had to laugh at this. Laughing at my own pain but still funny.
Recently, in my campaign, however, the issue is a bit the opposite. I'm in tier four of play in the fourth year of a campaign and the baddies have a lot of magic at their disposal. I hate taking a character out of the battle with hold person, banishment, polymorph, etc. But it seems absolutely necessary to make combat a challenge. I don't feel
too bad. After all, its kinda on the other party members if nobody casts dispel magic, counterspell, etc. Also, it is something intelligent magic using baddies would absolutely take advantage of. Also, it is better (less boring) than adding more baddies and/or bloating their hit points.
I'm backing Matt Coleville's
Flee, Mortals! Kickstarter campaign and I like some of the ideas he has for monster abilities and stat blocks. I'm always looking for new mechanics to keep monsters fighting longer and countering player powers in ways that are more interesting then making players lose turns or just adding HP, adding more combatants, or just counterspelling. Things like abilities to transfer damage or effects to a minion, limited legendary actions and nova abilities for non-legendary mooks, etc. can keep things interesting.
