I was nosing around online today for the dates we'll likely be visiting over the summer and I noticed a surprising lack of ADRs open for dinner at Tusker. Considering prime spots at 'Ohana dinner, Cali Grill dinner, BOG and all of the early pre-park opening character meal slots were there and quite plentiful...it says to me one of the two things.
1. people are doing what you suggested doing
2. Disney is taking a bunch of the slots out of the system to make room for the package slots.
Still, when Disney offers package dining, it's always independent from normal ADRs. So, I wouldn't bother booking anything right now.