I honestly hope there will be no more crossovers. The problem I see is what if some viewers are unfamiliar with the crossing show? And if it's a two parter that airs on both shows (like the crossover with 'Without a Trace') those who don't follow the other show might not tune in to it and not know how a case turns out. Or they won't tune into either. As mush fun as the idea of a crossover might be, I think shows should be left to their own realms. That's just me though.