What excites me as a DM is when things happen in the game that the players are still talking about even months later. That's cool.
I want the players to have fun and enjoy the game, and I love it when they try to influence the world. I never try to kill their characters or aim for a TPK because...
Personally I'd always go back to the original and ignore later metaplots for any conversion, but I may be biased as my preferred setting is Harn which explicitly lacks a metaplot by design.
I'm also a much bigger fan of Birthright than many of the other settings.
As a DM, I prefer to err on the side of a sandbox.
When I run a game, I'm not trying to tell a story; if I want to tell a story I'll write another novel. I want to put sufficient elements in front of the players so that they can create their own story from their actions and choices.
I'm definitely curious -- though I'm not sure about the budget stretching at this point. Then again the setting I want most is one I'm sure we won't get for 5E: Birthright.