I've been pretty critical of Guilbeau, but watching some of the all-22 I'm now starting to see that the problem is bigger than him. Derek Williams cannot QB the secondary like Taaffe and he seems to have lost some of his situational awareness. Manny is awesome, but he also seems to thrive on an island. Littleton is a true freshman and is doing great with that context in mind, but he can't lead the DBs. I think Guilbeau is the veteran DB most likely to be tapped as leader when Taaffe and McDonald are out, and he is not fit for that job. He both tries to do too much and also doesn't do enough. Filsaime is kind of in the same boat when he's in.
But Guilbeau is not as big of a liability as he seems. With Taaffe back to run the secondary, I think we see improved play across the board. If he still sucks, then I think you have to pivot to someone like Phillips and hope for the best.