One thing I've been thinking about since the NL adopted the DH this season is the potential of MLB realigning from the AL and NL to East and West conferences with there being no rule distinctions. Unlikely, but not something I'd put past Manfred.
If they do it (with each conference remaining 3 divisions x 5 teams), the A's moving to Vegas would make the realignment that much easier. They are one of 6 teams on the west coast, so them moving would put the number at 5. Plus Vegas could be in the same division as Arizona, Colorado, and both Texas teams.