I don't have a PS4 yet, but I might get one by the end of the year or at the latest when UC4/FFXV (depends on what releases first, so probably UC4...) release, but some unannounced games that'd probably make me get one as well are:
Ni No Kuni 2
Dark Cloud 3
Final Fantasy VII remake
Persona 6 (or a next gen version of Persona 5)
Overall if Japan would get its act together and managed to create another awesome JRPG generation like the SNES/PS1 gens were, then that'd be absolutely awesome.