Hmm I think the pricing seems fair. I mean PSOne classics are $5.99, and $9.99 for the iconic games. So PS2 being $9.99/14.99 seems right. Correct me if I'm wrong but Nintendo charges more on the eShop for N64 games compared to Sony with PSOne games.
Perhaps the best pricing model to net more digital revenue would be pricing all games $5.99 for PSOne classics and $9.99 for all PS2 classics.
And make PSP emulation possible as well! PS4 and PS3 should run PSP games too, priced at $8.99 for all software. It would only push more digital sales by giving the software access to two more platforms.
However, they should give access to the games for people who have already bought them.
Not sure how the emulator works, but I think it should be possible to just enable the PS4 to play PS2 discs as well. My guess is the currently released games were tweaked to be able to run, so not every game is currently compatible/run-able.
Gaming on: PS4 Pro, Switch, SNES Mini, Wii U, PC (i5-7400, GTX 1060)