But that show is weird cuz it has, literally, two male leads of equal standing. See? Hotch and Rossi (the replacement Gideon) are given the same position/status.
It's cuz they have the team leader type (Hotch) and the old guy with a lot of experience (Rossi/Gideon). Rossi and Gideon aren't the leaders for various reasons - Gideon had some sorta breakdown before the series started and Rossi left the BAU ages ago to write books on serial killers. But he came back for VENGEANCE.
Why, yes, Rossi is one of my favourite characters. He's a bit of a jerk <3