If there would be no parser and I really want to have better results by kicking the bad ones, I'd just kick those of my party who [i]seem[\i] to be the problem.
I'd try to [i]proof[\i] it by looking on the attacks (rotation) they perform written in the chatlog and on the numbers shown there, if he does something like 24 GCDs per minute and his gear.
If I don't like his 'different playstyle'... kick.

I guess that's better than using a parser.