Unfortunately host migration will never be a thing unless Unreal Engine 4 adds support for it. It requires a complete rework of their networking engine and is beyond the scope of our game. We have thought of ways to convince players not to disconnect a server (by rewarding good hosts, or marking bad hosts, or rewarding players who get effected by it).
Virus needs the speed, but I have considered adjustments. Laser Tag is already very slow and its speed was reduced a week after its release. Snowball Battle was a bit too fast, but it's using the lobby speeds and I felt it would be okay. Since the release of it, I've been helping Foohy fix a major regression and on vacation so Snowball Battle won't be fixed in time, sadly. I do want to bring it back for non-holiday, though. SDNL is not released yet.