Yeah, for Peach I was also thinking about the off chance that she pulls out items like: Bob-omb, Mr. Saturn, and Beam Sword. It's rare, but always fun (and scary) to see it happen at tourneys.
But yeah, I see what you mean about Diddy and his nanners. They are his bread and butter, and you could preform some unique advance techniques with them. See, I've tried learning the ins and outs of Diddy, however, my reaction times are too slow to pull off some techs. Glide tossing (well in general), banana dribbling, etc, etc, my hands are way to slow. I don't know how people could preform such things.