I don't see why people think this move would make the Spurs a sudden title favorite.
Honestly, I don't think it increases their ceiling all that much. He is a fine player, but he's not a star.
For all of the love people give his offensive game, his field goal percentage is still BELOW the league average. And his defense, while improved lately, is still mediocre.
Definitely a good player, don't get me wrong, but honestly I wouldn't trade Splitter for him. Splitter is younger and has more upside. Al Jefferson is old. Why do the Spurs need another old player, who isn't anywhere near as efficient or cerebral a player as the other players on their team?
Splitter is FAR more efficient offensively, no worse at defense, and is a better passer.