Did this whole pairing seem to come out of nowhere for anyone else?

Nope Uiharu was interested in Misaka from the beginning but as a fan, if Kuroko was not around that pairing would have poped up alot more

Looks like Uihara has no neck here. Or maybe I need glasses [I really do actually...]

? Her stance looks pretty normal to me. From this perspective I wouldn't expect much of neck exposure, considering the fact she's playing (trying to play) violin.