I think a good part of the problem has nothing to do with GV or IT, but with the mediocrity surrounding them. I'm looking forward to seeing what happens tomorrow, when hopefully we'll see something new and exciting and not fishy on the court to start the game.
And I'm not ready to say he can't, or shouldn't, play with Cousins. I was in line with that thought process last season when Evans was around, because at that point it was just too much. We had too many players who needed the ball to be successful. This season? It's a little different. McLemore doesn't 'need' the ball. He's a catch and shoot player, so he'll get his looks on the break, on set plays, or as a kick out for a driver / Cousins double team. He's not going to make a play with the ball in his hands. Whoever we trot out at SF and PF also don't need the ball, because odds are that player isn't very good. That leaves Cousins and Thomas, two players who occupy opposite space on the court. I don't think it would be an issue, but it's hard to say without seeing it.
IT has become a very good penetrating guard coming off high screens. This means that he is going toward the rim and his big man needs to be of the pick and pop variety, which isn't Cousins' natural game. IT has been shooting reasonably well from three point range, but look carefully at his makes. He shoots his best percentage on wide, WIDE open three pointers. The kind where nobody is closing out on him. He isn't a natural catch and shoot guy, which limits him on kickout shots from double-teams in the post.
Vasquez, on the other hand, is a mid-range pullup shooter. We are starting to see him run elbow pick and rolls with Cousins with Cousins rolling to the rim. That puts both players at their best position for making a shot, Cousins under the basket and Vasquez at free throw range. Cousins is also in good rebounding position without crowding the shooter.
I'm not saying that IT and Cousins can't work together, only that Vasquez SHOULD be a better offensive fit with Cousins.
Defensively, IT is the better defender, but I still see inconsistent effort on his part against second-tier point guards like Teague.
If I had to make a prediction, I don't think either player will be with the team next year. I think IT is going to get a decent mid-level contract somewhere and the Kings aren't going to want to commit much to keep him around. Much as I would love to get Parker or Wiggins, I think the Kings will end up picking up Smart or Exum at 6 or 7.