Artistically, of course, it is wonderful to work with characters who come from an uplifted species. I get to stretch my imagination, and the reader's, exploring what sapient dolphins or chimps might feel and think, under the pressure of such development, tugged between both the ancient instincts of their forebears and the new template being imposed upon them by their "patrons."
I see nothing philosophically wrong with animal uplift, but the concept is freighted with some alarming anthropocentric baggage. "Uplifting" animals to function as peers might sound liberatingly utopian, but the very notion of "peer" suggests, at least to me, beings more or less like ourselves.
As a potential "patron" race, we're bound to project our own preconceptions of personhood onto the animal species in question; our future uplifted friends might very well thank us, but they'll be doing so in a singularly human-like manner (in which case we might be better off poring our energies into the development of sentient machines instead of pretending to be faithful to a given species' zoological source code).
Well-intentioned as they are, proponents of animal uplift labor under the dubious assumption that there's something innately wrong (or at least existentially limiting) about animal-hood. On the other hand, anyone who's had a close relationship with an animal is bound to question such certainty. Sure, it might be nice to jam with my cats about quantum theory, but I sense they're quite content in their feline-hood -- and who am I to deprive them of that?
I'd go so far as to propose that animals are already engaging us in a meaningful dialogue, although perhaps not the sort of dialogue depicted in Brin's canon. That we've yet to understand our fellow mammals on their own terms remains an emasculating reminder that perhaps our "patronage" is neither needed nor desired.