I'm personally excited that Microsoft now owns Zenimax (Parent company of Bethesda). Lately Microsoft has been doing a lot of good in the gaming scene as far as treating their IPs. What really excites me is they bought Obsidian a few years back which was the company who made Fallout: New Vegas and never got a chance to make a second one because of some bs that happened between them and Bethesda. With Microsoft now owning the IP for Fallout they can just give it to Obsidian to make another Fallout game which is awesome.
I don't think that any large series like Fallout, Elder Scrolls, or DOOM will become exclusive because Minecraft didn't. I do think some of the secondary series like Wolfenstein or Starfield might go Xbox/PC exclusive.