Al is what he is, and he's still improving as a player. He's come a long way even since getting to Utah. I don't think the problem is Al directly. The first problem is that the Jazz are playing him at center when he really plays more like a PF. He doesn't play the pivot and likes to stay just outside the lane on both ends. The other problem is that Al should be a 2nd option on offense, but the Jazz don't have an elite scorer, so he becomes the first option, and the game slows down to let him operate. If Al were playing in LA with Kobe or playing in Miami with Lebron, he'd be a solid 2nd option to score in single coverage. He'd play a bit of pick and roll, he'd score from 8 - 10 feet, and everything would be fine. He'd basically be like Zach Randolph in Memphis. He wouldn't have to go down to the block and be option 1 on every other possession. However, the Jazz have no true first-option on offense and have to rely on Al. This is probably also why Al takes plays off on defense.
On defense, he's not an elite defender, or even a good defender. He's okay in post coverage. But again, he's not really a center. If Favors is on the court, then Favors anchors the defense and we don't get torched. Now that Favors' offense is finally starting to come around, we can play Favors and Jefferson together and not really lose much if anything offensively by taking Millsap off the floor.
Overall, I think people are just expecting too much from Al. You want a 20-10 guy who works hard on defense, plays in the flow of the game, scores efficiently, gets to the line, and doesn't really have any flaws. There just aren't many, or any, of those players in the league. If we had Blake Griffin, people would be complaining about his lack of offensive moves and lazy defense. Chris Bosh is still soft and doesn't defend or rebound all that well. Etc.