interesting thread. I'm not sure if "diluted" is the term I would use, but I will say that sometimes I feel like the rush to be a part of what is "hot" can result in some problems.
For example, scholars have produced some truly wonderful transnational histories in recent years and I think the move toward transnational history is, in general, a positive one. But, as someone who does not study Western Europe or the US, it sometimes feels to me as if the paradigm exists to give Americanists an excuse to talk about non-American regions without learning another language or without properly understanding the trajectories (and what influenced those trajectories) of sometimes radically different historiographies.