Honestly, I always thought Toadette being playable was neat, and I don't hate the Mini Marios... but yeah I do prefer playable Toadette.
Toadette being playable is a lot better than just having colored Toads in my opinion. She's a proper individual whereas Toads are just a species within the Mario universe. She's not flawless, she's basically is just female Toad, but I think it's an improvement. Mini Marios just never had much goin' for em' in my eyes. I don't hate em', they're neat, I just could never really get attached to them. They come from a title I played for a bit that never left a lasting impression on me at all, and I rarely see folks talkin' about em' nowadays. I do think the concept is neat, though, and I like the design and animations. They're cute .I don't think I'd say they're worse than Toadette, since neither are bad in my opinion, though. I just prefer Toadette.