Hey Einstein, when I think about what makes a portable game more like a console one I have started to ask myself: What do we hire portable games to do for us now?
There may have been a time when a portable game was indeed meant for travel or any other away-from-home-console context. It was a largely inferior experience either in presentation or control experience. Since, as we know, technology has steadily improved and the portables we have today are now capable of delivering similar experiences to what we are used to from our home consoles. (and even some we are not: see 3ds).
Perhaps not surprisingly, more and more people have come to play their mobile (including traditional portable gAmes) at home.
http://gigaom.com/2012/03/22/where-is-mobile-gaming-happening-at-home-in-bed/As such I realize that I no longer really differentiate between the "portable gaming experience" and the "traditional home gaming experience"...the games are now good enough for me that I am quite comfortable choosing to play on either platform depending on which game title I desire to play at any given point. Actually, as my lifestyle has changed, I depend more on portables for convenience,..you could very well say they fulfil the primary game experience role for me :p
This is however dependent on the type of player...as someone who does not play twin-stick shooter games for example, the portable experience is now analogous to what I would play on a console.
To a gamer that, as an example, expects such controls in a full blown console experience I imagine portables remain unsatisfactory and that will not change until they can have an uncompromised experience. Perhaps this will be CoD Vita?
My main takeaway is really that it depends on the level of user and the types of experiences they are looking for...but I suspect that for many users, portable experiences can now ably fulfil primary gaming roles