Yeah, I had the same experience here. I underestimated the Gothitelle line at first but it actually did a good job for my team thanks to getting Psybeam right off the bat. It even gets Psychic not too late of a level and Gothitelle's cry reminds me of Psycho.
Its Frisk ability combined with Thief was helpful when hunting items. I was actually proud of my Gothitelle and it quickly became a favorite for me.