An ethnically diverse parish shouldn't be striving to make the Mass a smorgasbord of cultural contributions; that's the purpose of the ubiquitous potluck. The Mass ought instead to reflect the supernatural oneness God desires: ut UNUM sint. That's another reason for the Mass to be in Latin: it is a universal language, the Church's own, and belongs as much to one culture as it does another. It's the ultimate in "inclusive worship:" armed with a missal in Latin and in his own language, everyone is able to understand the Mass. Everyone.
The drive for diversity often proceeds from a misguided notion of inclusivity. It ought to be obvious to people (but apparently isn't) that unfettered diversity does not lead to inclusivity. There is no way to "include" the "diverse" preferences of ten people at a single Mass, let alone the preferences of hundreds. Someone is going to be Left Out. Inclusivity doesn't mean accomodating people's every twitchy whim, but accomodating people as people. You are included in Mass because you're allowed to come.