Overstreet was a late enough addition that it's somewhat easy to forget that Texas landed two quarterbacks in this class, and even more specifically, that Texas landed two quarterbacks this good in this class.
Overstreet's abilities run counter to those of Connor Brewer's, which means that — should he stay at quarterback — he'll have a chance to carve out playing time in specific sub-packages that offensive coordinator Bryan Harsin likes to run. More in detail, Overstreet can run the packages that David Ash started in last year, except that Overstreet is a considerably better athlete and runner.
As a thrower, he's somewhat difficult to gauge. From a mechanics standpoint, he's raw. He flicks the ball at times, rather than following through. His release point varies, and he throws off his back foot often. And Tatum (smartly) put him on the move a ton, rolling him out and getting him on the edges of the defense. Of course, what that means for us is that we have relatively little film of Overstreet dropping back five steps, transferring his weight and making a throw that he might have to make out of the pocket in college. That's not to say that he can't do it, and he does generate some arm strength when his mechanics are right. It's just that we don't have an extensive history there.
But Overstreet shines as a runner, when he combines vision, strength and well above-average speed to make a living. He's quicker than he is fast, and he isn't the type of player who is going to make five guys miss and outrun everyone to the end zone. But he is the type of player who can hurt you in the quarterback run game, when he gets behind his pads and makes you feel the blows. He's more a smooth athlete than an explosive one.
His size (he's listed at 6-2 207) and his ability to run have caused some to project him as a safety, or even outside linebacker. And it could be that he ends up there in college. He could do well at either position, and he demonstrates the requisite athleticism and physicality to make that switch. But for the start of his career, he'll be a quarterback, and with a skill set that's dramatically different from the other quarterbacks on roster, he'll at least have a chance to carve out a niche there.