I'm leaning towards "yes," especially since I think the idea is getting traction online. The D-Pad issue is becoming more prevalent--yeah, we can always buy a Pro Controller, but the Joy-Cons are so appealing that I'd really prefer a couple of those instead. Count me in for buying one; those VC games won't do with an analogue stick.
Unsure. It would have to replace the analog stick and not the buttons, though, right? At least for VC purposes, and for using it separately. I guess either way, that limits its usefulness. Unless you can cram a d-pad and and analog stick and buttons on the dang thing, but that seems unlikely.
I voted No. They have the Pro Controller for that. I think this is it. Mainly because of Paul and Brandon's thoughts. While the D-Pad on a Joy-Con solves one 'problem' it also creates another for one of the core functions of the device. If it happens, it won't be for some time.
I'm guessing "no" because Nintendo think the Pro controller is for anyone who wants a D-pad. However, if enough people complain about it, Nintendo may release one at some point. They do like to make da monies on accessories.