There is a division among fans and in the media about how Saban is approaching his defensive backfield.
Cound me among those who believe he is doing some good things. Saban has a scheme he runs. Its a lot of zone coverages, some man-man coverage, and no press coverage. You see a lot of formations that call on the db to come up in run support, which you never saw in Jim Bates' defense.
Sam Madison and Patrick Sertain were not the kind of players that fit Saban's defensive scheme. They are adept at bump and run one-one coverage on great receivers. Their talents were not supporting the run game by making tackles, sometimes in the backfield.
So, Sertain had value and he traded him. Madison was due a roster bonus and he released him. I like both players. I will miss both players. But, its clear that his direction is to find players who can play in his scheme.
I don't know much about Renaldo Hill or Will Allen. But, I do know that both are good dbs who teams discarded. And when I look at the teams that let them go, I realize that they are teams that play the man coverage, and they weren't "getting it done." That's why Madison and Allen effectively traded places. Madison will probably have some success in NY, and maybe Allen will be a good role player in Saban's defense.