I don't think there's any question that lowry is not playing the right way. He's a very good player with some significant limitations.
The real question though is, is he playing like this because of his team mates/coach/injuries, or this is his temperament. Because, as good as he is, if this is his normal play, not sure I want to commit major money to him long term.
As for JV, I've been saying this from the beginning, he shouldn't start. He's a horrible defender right now and I can't understand why his development is tied to a start role. Let him come off the bench, give him a tighter leash so he earns his PT and slowly increase his role. I'm pretty disappointed with him so far, I was expecting hustle, rebounding and shot blocking and he's been fairly average in all 3 areas.
Rebounding is particularly worrisome, virtually anybody who plays alongside Bargnani
gets a major boost in rebounds JV averages slightly under 8 boards per 36 minutes which is quite low ..