I agree. I was always kinda bummed out that you can't keep a Meloetta in her Fighting Form (which I know has an official name that I can't remember right now)
One because I like the design fighting form better, and two...Normal/Fighting. That's actually kinda cool. I already have a Normal/Psychic type -hugs his Girafarig-
I also kinda wish that there was some way to keep Zen Mode Darmanitan. Like I know how the ability works, but I wish after battle and stuff it at least stayed in that form. I wish you could start a battle with it in that form.
Don't forget to check out my MegaTen themed webcomics at http://www.drunkduck.com/user/Strain42/ (Currently Updating: Persona 4TW Add-On M-F)
While I agree that it should be kept permanent somehow, I can't help but laugh at the naivete of sending GameFreak a message about this, as if a) you're the first one to ever think of it, and b) they would even consider making this change when there are hundreds of more pressing issues they have to deal with first.