IMO it's lacking first because it's only on T-Mobile, which is one of the smaller carriers in the U.S, so there is less of an incentive to develop apps for it, because there are inherently less users. Another issue is that T-Mobile has a very small service area compared to AT&T or Verizon, so applications that demand connectivity to work effectively would have trouble. This is a big issue for companies that develop applications for serious business/government use like ours (emergency management). Not being able to listen to your Pandora radio is one thing, but not getting alerts about an emergency is totally different story (this is just our case in particular).

This might sound silly, but it's butt-ugly.