I wouldn't call the heart of Central West End developing, rather developed, but you'll find that the outskirts of the neighborhood have been steadily improving over the last few years, especially the area north of Forest Park (but still south of Delmar) and the area east of the neighborhood as you get closer to SLU.
The metro stop at Barnes is easily accessible from the neighborhood and buses are pretty easy to come by as well. You can check all of that out on Metro's Web site:
Metro
All in all if you think you can cash flow on it, I think it's a pretty good call. it's still, even after all the new neighborhoods in St. Louis that are now considered cool,
the place for the young crowd. I suspect you'd have no problem keeping it rented.