Quad core Kal-el is already being put in Tablets. It'll be in smart phones shortly. A6 is will be here next year as well. You can buy joysticks for smartphones that just stick on the screen. You can do so much more with iPhones and Android devices that you're going to have to carry around two devices if you buy this.
You also assume that the Vita is meant to be carried around with you 24/7. You aren't going to pull it out in 2-5 minute intervals to play Uncharted, Final Fantasy, Persona, Zone of the Enders, etc. as you would Angry Birds, Cut the Rope, Infinity Blade and so on. Throw it in a bag, briefcase, car, desk at work, etc.
Portable gaming doesn't mean having it in your pocket at all times.