The problem I foresee, along with bandwidth caps, is the size of the HDD. At 500GB, It means that I could have theoretically only 10 full games before hitting the cap, and that's an unrealistic scenario that does not take into account save files and the OS files. So when will they make available 2TB PS4s? :P
I really thought the additional characters would be like Catwoman. Challenge maps and free-roam with some short missions to add to the too short campaign. 7 bucks for what amounts to a character and two little maps seems really pricey.