Get a 3DS.
A 3DS "lite" really wouldn't add much, anyway. Except maybe actually integrate the damn second thumbstick like it should have always had.
It'll be years before that.
I'm getting 3DS, though I have my doubts if I'm making the right choice
They won't add another analog stick, because that would be totally new console, not a revamped 3DS. Keep in mind all current 3DS owners have to be supported by future 3DS games, which have to be designed specifically to operate using one thumbstick not two. Otherwise 3DS-one analog stick users would feel betrayed by Nintendo at such an early phase of console lifecycle.... Lastly, nintendo never changes arrangement of controls within same generation of console. They will make 2-sticks console in the future, but it's gonna be 3DS successor, another generation of handheld, not it's revamped, lite 3DSi or whatever they gonna call it incarnation.