That's what FH and I are worried about, as well. We worry that Disney's going to consider DDE too much of a big "to do" now and that profit margins are going to go down...and they wouldn't roll it back just to Florida residents, they'd cancel it outright
I'm an AP DDE holder, and I worry as well - look at all the posts about ppl worrying about their cards. They are so overwhelmed in the office and had to update their phones and add staff. At some point, someone at WDW is going to evaluate the relative worth of having opened it up to AP holders. That just makes business sense after making a major change like that.
Interestingly, as a single diner, I notice that using the DDE just means that I tip a little more, ie the total cheque really doesn't go down. It does make a big difference, however, with more than one diner.