Well, remember the problems that have killed Skirmish. Even though everybody wanted Skirmish, nobody ever plays it unless there's a generous event boost. Because of the player count the exp in Skirmish wasn't as good as GB. And so everybody played GB and nobody played Skirmish.
If this is done then it will have to be in some way more rewarding than GB for it to work. Perhaps the player can respawn like in Op Convoy, thus enabling the players to earn more attack and AA credits, and the game goes on until the objectives are destroyed or time runs out. If they have multiple lives unlike most game modes, equal or greater exp can be earned and they can have quite a bit more fun.
Perhaps the Harbor Assault equipment can be used, too. Like you can use APA/airlift on enemy points and for each one captured the team members will get bonus exp. This mode can really enrich the playing experience, being potentially a lot of fun and rewarding at the same time. Unless mixing the two is bad :P
