My opinion is that neither of the bosses should be customized. That was the point of the new server, isn't it?
Otherwise we are going back to EW 1.0, where exactly this customization repel new players. If you customize Core what's next? Someone will ask to customize Baium, and that will be the end of the server.
Who wants customized bosses could play in EW1.0
The only thing you could change to all raids is the chance drop, which in Alfa is x1 and doesn't response to a x10 server.