I don't see why it's an ignorant generalization, while I don't know the full specifics of the UTD refresher, if the student is like 99.99999% of the PADI OW divers out there, they don't have the buoyancy/trim/propulsion skills to get through that, nor are they familiar with the air sharing practices, so it would be a major hurt on the class for others when the refresher class is designed to take students from that agency or ones with similar training standards, and refresh them on the important points that may have been forgotten. NAUI/PADI/SDI, no problem moving back and forth between them for a refresher, it's all about the same. Moving to UTD is a completely different animal and I don't know of a single standard PADI course that has divers prepared to go into the team diving aspect. Also note that I'm not a fan of UTD in any way except for their heated body wrap, so it's not like I'm chest thumping.
If he's talking about the Essentials of Recreational course then that is an entirely different animal and in that case I would recommend taking that, especially if you aren't nitrox certified since you can get your Nitrox cert for no additional cost. Their Extreme Scuba Makeover also looks like it could be an interesting course and I'd recommend that no problem, but if they are offering a standard refresher, similar to the ones that NAUI/PADI/SDI et al offer, then no, I think it would be a very rare exception that a PADI OW diver could pass, mainly due to gear configuration/air sharing issues, compounded by buoyancy/propulsion techniques.