I'd rather play with someone who's never played a champion than a one trick pony
Because it should be reminded that if you're a one trick or hard champion main, you're invalidated from being good because you lack similar skill on anyone else. I hate OTPS so much I get disgusted and feel like losing if I have one on my team.
I honestly have much more respect for someone who's never played a champion but learning it in my game than an OTP.