You're already doing the number one thing that will make it happen. Buying TNGR. Keep those sales coming, and DS9 will follow...
CBS know very well that DS9 can expect to sell probably half the amount of TNG (possibly pessimistic), both on blu ray and in sales to stations, netflix etc. It just wasn't as popular, so they will take the TNG sales, halve them, and that will be either a yay or nay.
I would expect at this point it is seriously being considered, and they will need to decide soon. If they want to keep the momentum going they will need to have DS9 S1 out for the end of 2014 (expecting TNG S6 and S7 as early and mid 2014 releases respectively, we already know we get S5 in November).
The other thing to consider is that Trek becomes an extensive high-definition library post-remaster, that can be sold essentially indefinitely. This might drag up any forecasts based on pessimistic estimates of Blu Ray sales.
Expect to hear a decision early next year, I'd say at this point it is 50/50.