This is one of the few things I miss about being in a predominately clinician/clinical role.
When I was at the VA, our experience with the Argosy's and other the other Free-Standing Professional Schools of Psychology were NOT good! University-based programs served us much better---this seems largely due to their smaller class sizes, which offered better mentorship and oversight, and of course, have more stringent criteria for admission on the front end. Otherwise, I might be slightly less picky than some on here, actually.
A desire to learn, and no obvious signs of PD or overconfidence for their training level is a good start. I mean, how much can you really conclude based on a short interview? I think any practicum student is a gamble given the variability in training programs out there...thus I knew that some students would require much more "work" than others. Students need to explore...and fail, to some some degree at least. As long as no one is harmed (you should be closely supervising at this level anyway) and the bottom-line isn't effected, I don't think it can/will be that catastrophic.