This is probably the way that remasters should be handled in the first place. Dishonored: Definitive Edition is up for pre-order on the PlayStation 4 in North America right now, and if you happen to own a copy of the original PlayStation 3 game digitally, then you'll be able to purchase the re-release for a heavily reduced $19.99. Everyone else will have to pay $39.99.
Of course, the really good news here is that the last-gen version was made available for PlayStation Plus subscribers fairly recently, so as long as you added it to your download list, you'll be able to take advantage of the discount. The polished up package is due out from 25th August, and will include the original game alongside all of its add-ons.