Walker is not a black hole. You have to use a lot of possessions and hold the ball during those possessions.
Walker has the highest PPT (points per touch) of anyone in the rotation, but only Vassell touches the ball less. He's pretty middle of the pack in terms of time of possession and dribbles per touch, behind all of the primary ball-handlers in that regard. Walker has been more of a finisher than black hole. Possessions don't "die" when he touches the ball. He shoots more than doing anything else, but a Walker shot is one of the best shots the team generates right now, and he hasn't been getting a ton of them.
I think he could develop into a good lead guard, though not necessarily a PG. He has the type of speed and athleticism that can bend a defense, but he doesn't seem to have the will. If he had Johnson's bull mentality, Lonnie would be the best offensive player on the team. He's going to have to learn to be a score-first guard who passes when he gets a defense to commit rather than a pass-first guard who only tries to score when he's open. Him ending so many of his touches is part of that, but he's still getting into the paint and looking to pass too much. And because Lonnie doesn't get consistent touches, he seems unsure of when to try to score and when to keep the offense moving. When he goes cold, it's almost always because he doesn't take shots, not because he's taking them and missing.