[Jeff Rodriguez]

Divide the field into three zones. Zone 1 from the wall to the beginning of the platform, zone 2 the entire length of the platform, and zone 3 from the end of the platform to the wall. Each 'end zone' corresponds to it nearest alliance.
Make the moveable goals neutral. When in zone 2 they don't count either way. When a moveable goal is in a teams zone it couts for 10pts plus the balls indside/ontop. Then, pushing a moveable goal to block your opponents ball chute would be giving them 10 pts. I think it would be a simple, fun way to spice it up a bit.

Here's a crappy little pic I whipped up fast to help explain the zone layout.
If you wanted to complicate things more, you could switch the blue and red zones, so your zone is on the opposite side of the field.