They won’t. Hear me out. When they bought Bethesda and Mojang they left them to go their own way. I am not privy to the agreements but unless it’s for console exclusives, don’t expect much of anything to change. Minecraft still runs on Linux. We might see a push to play together. Console parity for future titles. Wow on Xbox. But structurally, how Blizzard does things will remain largely unchanged. For better and for worse. They take a largely hands off style of business decisions.
All that being said, they’ll likely have a larger budget for hardware and being hosted on those amazing ocean servers, means less lag wherever you play from. Microsoft is a good collaboration company. They just seek domination. They don’t care how you do things as long as they own you doing it.