I'd have to go with Kira.
Banagher is a natural enemy to the newtypes such as Amuro or Kamille so he should technically be able to take them down. The NT-D system should also be effective against Kira's funnels but Kira's Strike Freedom has so many other weapons it might not be as effective as it was against the newtypes, plus it may not work at all seeing as Kira isn't technically a new-type. I don't think he would win though because I imagine everyone'll target Banagher first given his formidable abilities to screw over so many people.
Heero's got a very good system in the Zero System but the Wing Zero itself just couldn't compete with the likes of the far more agile gundams such as Strike Freedom. The Gundams in Wing seemed like they had far more amour and good take more a beating but weren't that fast.
Domon will get taken down because every other gundam can take to the skies and just rain down pain on him. IIRC God Gundam isn't really known for flying around and is a close range fighter.
Kira's has SEED mode which gives him a big advantage plus Kira's just an amazing pilot in the first place. He could take down entire armies while ensuring all the take downs were non lethal. That takes so much skill it's unreal and I don't think any other pilot has shown anywhere near as much skill. Also remember that the MSs in Seed seemed to fire lasers and Kira could dodge them all with ease. The MSs also seemed much faster than the ones seen in UC, AC or other universes with the possible exception of the AD universe of 00.
It's hard to say how powerful Qan T 00 was because I don't think we really saw much of it IIRC. I don't remember much about the movie but it was said that the Gundam could've taken out the entire ELS army if it had chosen to do so.
I don't know much about V Gundam either.