I agree with most of this but I put more blame on KP for not getting easy shots. I think we can all acknowledge that when he gets a switch with a guard on him, he gets the ball in the midpost frequently. That he's settling for contested jumpers from there is a problem, but I blame him. He settles way to often for a single dribble, turn around jumper with a fade away. He also steps back after most of the picks he sets which I don't really mind, but it means he's taking extra long jumpers instead of diving to the basket for what could be those easy lay-ups or dunks (for a guy his size, I feel like that'll quickly increase his FTA's moreso than anything).
You're dead on that a lot of his opportunities are contested iso's, but I think he settles because he's too comfortable trying to shoot over defenders when he has a pretty formidable cross over for a dude so big. The doubles have also turned him timid though, the 5 TO game being a good example. He gets a bit flustered and rushes his moves. This is all young player stuff mind you, I ain't upset or downgrading his prospect status. He'll pick up more as he gets stronger and gains confidence in his arsenal.
Also, I think it's worth noting that he's getting the second most touches per game behind Rose (and touches always skews towards the primary ball handler). Melo's fourth on the list (Rose, KP, Jennings ahead). Melo is confident waving dudes off and going after guys to his own detriment at times. KP would do well to take a few of those chances too, especially when a bigger, plodding defender tries to front him on the perimeter (those opening touches where they bring the ball up one side, swing to a big who then swings to the second guard being a prime spot). KP has the touches and if you look at where he's getting touches, he's top three in touches at key spots on the floor (post-ups, isolations, etc.); so there are opportunities if he chooses to attack. I really think he did assert himself more often earlier, he's relegated to more catch and shoots or turn around jumpers now; but look at the earlier portion of the season and I really think you'll catch a different player.