[EricH]

They'll stay with 4 divisions. Here's why (not in any way, shape, or form official):
1) Logistics/space. The only places that I know about big enough for Championship are covered football stadiums or temporary structures. Both need floors that are not grass. There are few of these around. Not to mention the ones that are there can only hold six fields without becoming overcrowded, and then where would VEX and FLL go?
2) Championship pairings: How would you do the champoinship rounds with six alliances?
3) With more fields, you can take more teams. This means more hassle with room for them all, traffic flow, queing, crate storage...the list goes on.