I think trying to unify rules in the UK is a good step towards some kind of governing body... well it's required!
So I guess there needs to be suggestions from a variety of different people to try and cover all angles.
Things to consider:
Age groups - are <18yrs considered juniors?
Weight categories - these are already pretty much standard
Fight levels - amateur / semi pro / b-class pro / pro.... etc. etc.
I personally don't think fights with no headshots should be even considered a level of MMA... my personal opinion (which im sure others will disagree with)... what about the use of 8oz gloves & headshots for amateur??
Anyway... unified rules... I think there needs to be some promotion on this so fighters, coaches, promoters, officials & referees are all on the same page.
Maybe you could have no headshots as something for juniors (U16 or U18) and then like you said bigger gloves and maybe shinpads for amateur.
Just giving my thoughts on that specific of it.