when you say RPG thats kinda vague. would dark souls 3 or Deus Ex be an RPG, or are you thinking more classic stuff like witcher 3? what about JRPGs, are you a weeaboo at heart or do you think anime fags are worse than furries? Most western RPGs seem to come to PC first like Divinity, Torment, Pillars, etc with a few making the jump to console. JRPGs are a mixed bag with very few even coming out anymore, although Final Fantasy XV is the big one. PS4 may have a few more like Star Ocean and Kingdom Hearts and next years Horizon Zero Dawn. The more "indie" JRPG stuff like Ys and other stuff is getting ported to PC now more and more, even becoming the primary platform as its hard for japanese devs to get japanese buyers and global audiences are more lucrative, digitally on PC.
but yeah if you are gonna stick to a 720p TV then may as well go for a slim, pro will do nothing for you. If all you want to do is play RPGs though, not really sure you need a console.