I don't think Peyton was a 'jerk.' He simply demanded the most out of his teammates because he gave them all he had. He was also very good at taking accountability upon himself when he played less than his best. Peyton was also the best (or one of the best) in the league when he played... you make a good point, Jacoby has leadership traits, but when he's not playing well it's hard for him to express them to other guys.
I don't think we need a jerk. I think we just need some more top-tier players who won't be looked at like 'jokes' if/when they have to try to light a fire under their teammates.
I think Q. already plays a major leadership role. Not just by talking to other players, but also by his actions and his superb play week in and week out. I think TY also plays a leadership role when he's on the field, unfortunately he missed >1/3 of the season.
As eluded to above, I think this is going to require us adding more high level players, staying healthy, and adding depth. We've got several guys on this team who are high-end players and seem to do well in leadership roles (Q, TY, Justin Houston, Leonard are the ones who come to mind, so 2 on each side of the ball). Unfortunately, both TY and Leonard missed time due to injuries, which doesn't allow them to be leaders on the field. We have significant drop offs in talent when those guys are gone.
We've got some young guys on the team who I think can step up and act as leaders as well if they improve from last year to this year: Rock Ya-Sin, Okerere, Turay (if healthy), Kenny Moore (when healthy), etc. ... Maybe Jacoby if he can play more consistently.
Hate using old Pagano lines, but "man sharpens man like iron sharpens iron" is coming to mind here. I just don't think we had enough strong iron across the board last year, which was apparent with major drop offs due to injuries.