100% Absolutely not. San’layn and undead should go to blood elves or forsaken, or their own HORDE allied race. The Alliance needs to stop asking for things that should be Horde. You have your high elf customization, go ask for more lore or whatever to support you. But these themes are what Horde have been asking for, and would fit the Horde, so no. Big no.
^ That’s the megathread for San’layn. On Horde. For those who want to support the ideas where they belong.