The league has been down this path before. Running QBs are a one trick pony and eventually they all get drilled and lose a step, usually sooner rather than later. Some of them adapt to actually throwing the ball accurately and making good reads while scrambling (Young, McNabb, McNair, Elway), but most end up just being really shitty passers who lose the ability to run (Vick, RG3, Kaeperbro, Tebow) eventually turning into interception factories. Very few straddle the line (Culpepper, maybe Wilson). The league has been through this trend a few times over the last couple decades and every time pocket passers are declared dead, they end up dominating the game all over again. Wilson in the SB last year stands out as the lone exception to this in the modern era and he was backed by arguably the best (and most roided up) defense since the 86 Bears, plus the best active RB in the league.
RG3 is just the latest in a recurring fad of running QBs that turn to shit.