For example if affliction is stronger than destro all the top gladiator spots are taken by affliction warlocks and you HAVE to go affliction even if you enjoy destro or not have access to titles.
How is this different from what it is now? The only difference would be that the overall amount of gladiator spots for a class -will- be slightly higher (or lower) because .5% of all teams is less of some (and more of others) than .5% of a class.
Titles don't matter at all. If you're good, people play with you even if you don't have titles, as long as you can prove you're as good as you say you are.
So basically you think class-specific gladiator is bad because people could reroll? Just like they do now?