Tbh if you keep the 360 and will start to play online again you will have to pay again. And your ps3 has free online play so you wont need to pay if you want to play online from time to time. Plus as you mentioned it is a bluray player.
And as you said it has the Jrpg etc. and exclusive bonus.
I would try to sell the 360 now before the console might get a price drop you can always go and buy it again if it drops in price and you miss it.
But I guess selling a PS3 would give you more money for your WiiU.
What if you keep both and just sell some games you actually never played? Or already finished and wont touch again?