Honestly the only incentive existing PS3 owners are waiting for is more games that they care about, a cheaper price helps as well.
They've already got COD locked and I doubt they'd go through the holiday without a temporary price cut. In the UK they've already done it for certain releases. So I don't anything you've suggested is daring or unlikely
This year should be the PS3's last holiday outside of Japan. Beyond 2015 I think the only game the system will receive is Fifa.