Port would be if it needed to compete against the financial power of 'only' 5 Vic clubs...It'd make the WA clubs look poor.
For one, I'd say they'd be looking at roughly doubling the salary cap.
If their were 12 teams, and still limits on football club spending - I don't see it as a problem.
I'd be interested in seeing if the AFL went to a zone system - where their was greater community connection, if many of the interstate supporters of Victorian clubs may drop off- as their friends, brothers and sons would be playing under the potential of playing for an AFL club in their area- Might be like the old days again...
Also, the extra benefits for playing for a Melbourne club, with all the extra press, media personalities (their bias) and exposure, GFs always at the G, would need to be compensated for in some ways to create a fair competition- both by having 12 teams, and also economically.