Tackling has evolved over the years, most CB's or even just DB's never really wrap up and tackle, they kinda hit the knees or go a lot lower.
As far as Rouse, I guess you want him to not slam into guys and have more of a tackle approach. I know what you mean, there were a couple times where he hit the ball carrier with his side and other weird ways. But if hes not getting hurt, and thats how he plays, then I'm happy.