One good game, and he went from being a Stretch-4 to a Point-Forward. (I guess four guys like Kyle and a Center, and you'd have a complete team.) How many times this season has Fathead made more than one 3-pointers in a single game? Twice. Two times he's made two 3-pointers in a game. And we all saw what happens when he's put on someone like Durant. It's kinda hard to be either a Stretch-4 or a Point-Forward when you don't stretch the defense, you aren't strong enough to post up forwards, and you really can't defend like a forward.
You know what a "taint" is? ('Taint your ass and 'taint your balls neither.) With a few exceptions, "combo" players are the taints of the NBA. That's because they get forced into the worst of both skill sets by good teams. They can be good players - except in those situations where they aren't.
I've said from the beginning that Kyle should be able to develop into a useful role/situation player. Boris has the strength to post up a lot of guys, and the handles to go under/around a lot of others. His skills and physical attributes are good enough to actually dominate in a lot of situations. Kyle is adequate in a number of areas. Which, translated, means that he gets his ass kicked about as often as he kicks ass. He'll have some good games, depending on who he's matched up with. But he needs work and improvement before he's consistent enough to be a meaningful playoff player for the Spurs.
BTW - since nobody has mentioned it, the one noteworthy area where Kyle has improved is his in-between game. So he's shooting a lot more of those shots this season, and his FG% has improved. Did you see him on that fast break against Memphis? A good Point-Forward would have taken it to the rack. But Kyle gets run down from behind a LOT on fast breaks, and doesn't have the athleticism to adjust at the rim to be sure he doesn't get blocked. So Fathead stops a fast break to pull up and shoot about a 14-footer. THAT is his comfort zone. To his credit, he knocked it down. But even a good percentage on those shots is a lot worse than the layups that fast breaks should be getting.