A few thoughts:
1) As long as it's privately funded and doesn't mess with Reading Terminal Market (tho some small businesses might get forced out), I'm with it.
2) The City will have to finally put some serious money into SEPTA, particularly into Regional Rail. The truth is, you shouldn't really need to drive to NBA games. The proposed arena would be a couple blocks from the Broad Street Line, Jefferson Station (for RR), PATCO for South Jersey folks, and directly above the El.
3) Rent has already been exploding in that area.
4) Nobody over the age of 25 goes to the Gallery.