I am not an expert at evaluating cheese.
But I have to say, as a DM I really like it, when players find smart and creative ways, to deal with combat, instead of just headbutting into everything. I don't mind if a combat becomes one-sided here. The encounter was still a challenge that was solved with a good plan, instead of just raw stats and luck.
Of course to keep encounters a challenge, the DM has to make sure the same trick doesn't work in every fight. But that is a matter for future encounters.
