Well I reckon I'm yet to reach my peak, but it's an interesting theory.
Slappo was never quite the same after he did his knee, but there have been others I guess who faded out of the game quite early - Slappo's bro, Sumich, even Scott Watters is half Croatian and he was finished before 30. Darren Gaspar is finding a new lease on life and his career now that he's over his injury so he can't count, Travis Gaspar is one big walking injury, Tony Modra could have kept going - how old was he anyway?? Grgic, Jurica were guys whose talent (or lack of) finished them early, Didak is still young enough, and appears to have enough of "it" to maintain an AFL career for a few years yet, and old Grizzleguts is still capable of pulling on the boots and getting out there (well according to his good self anyway). I think as a "group", the Croatian players probably fair quite similarly to nay other group in the competition. But to answer your question...
Has Pav reached / past his prime?
Umm.... no.