Riverside Park, though a nice place in itself, has been a lower income area for quite some time. While there may be some new developments on the southern portion of the Park (closer to IUPUI and downtown) the bad economy has stalled most of those proposals. If things perk up, I would say this would prove a desirable area for condos and mid-price apartments, but right now, the neighborhoods on either side of the white river from between Michigan Street and 38th Street are pretty working class.
The one exception to this is the area around Marian University, which is stable and in good shape. But it seems to be strictly owner-occupied so not a lot of rental opportunities around there.