As a fan of the Age of Empires series and a Linux user, I’d really enjoy if Linux support was considered (read: I wouldn’t play AoE4 if it required the use of a non-free operating system).
The Linux port of Relic Entertainment games like Company of Heroes and Dawn of War has already been worked on by Feral Interactive, so I’m pretty sure such a decision would be more about politics / business than technicalities.
Also, if the help of an experienced Linux developer with a short but fruitful experience working on a AAA RTS game was needed to make this happen, I’d be more than happy to volunteer.