I usually like Boss Rushes before the end.
In most cases, I feel like it makes the build-up at the end more epic because you're reliving some of the more dramatic moments of the game that preceded. Also, usually the bosses are a lot easier because you're stronger in some way, and that feels pretty cool, I think, to handily defeat something that was challenging before.
There are definitely exceptions, though. Wind Waker stands out in my mind because being stronger really just means more health, so it doesn't do a great job of demonstrating how far you've come, etc.
Might be time for a new sort of boss rush, though. For example, a next-to-last boss that summons the other bosses and you have to fight both at the same time. I already really liked the dinotank boss in Bonk's Adventure, which had attacks that emulated all of the previous bosses...