There is a similar topic out there; "RJs -- Savior or Damaging." I think the general impression of RJs depends on where you're coming from. For example, CLE
has become nearly dominated by RJs. This is a place that used to have many, many mainline flights, so people here are likely disappointed.
But I think that disappointment is minimal when compared to how estatic the small and medium-sized airports are about the RJ
phenomenon. You gave the XNA
example: this is a market that probably wouldn't support a mainline aircraft (maybe an F-100, nothing more). The CRJ has enabled people in Bentonville to get to LAX
non-stop, and on a jet aircraft. I think they like it.
In short, though, RJs will become more prominent so long as the market demands more frequencies, fewer turboprops, and more nonstops.