some people would feel that any "new" exchange would be an interloper

I really dislike that, it makes me uncomfortable that some people would seek to "defend" their feelings for the exchange by dismissing the idea of another exchange.

The fandom can definitely support additional Draco/Hermione exchanges.

I agree completely, and whatever some may think, fandom is more than LiveJournal-based. There are many people out there. On the internet! :D