Obviously Grier is hiring staff based on Flores's input so IMO it's pretty obvious he's the guy.
While I'd prefer Richard, the optics of him yelling at Vander Esch and Lee on the sidelines with them doing the equivalent of rolling their eyes makes me worry that his level of intensity might have a similar effect as Saban's dictatorship did among professional millionaire players.
Beyond that, was watching Florio and Chris Simms this AM discussing how the Rams admitted to anticipating plays because Dallas broadcasted their formations due the way their defenses lined up, hands on the ground, etc. Both of them were specifically taking Garrett, Marinelli and Richard to task for being oblivious to this.
So while I think he's still preferable, the above plus him being the only DC ever fired by Carroll causes enough concern to confirm that like all the other possibilities, Richard has his own fair share of "warts" IMO.