Is Dobbs a good practice player? Better than Dormandy?
Hard to say since we actually see so little of practice. The coaches don't share very much nor do the players of what they see when studying video. Most of the "insiders" still do not get the intimate details that come out in film study. Often times, practice plans make things look different than they actually are.
Last year, Worley appeared to be constantly throwing behind receivers during the open portion of practice. Dobbs and Peterman appeared to be hitting them in stride. Many here went nuts claiming that Worley was wildly inaccurate and one of the others was going to start. A while later it came out that Worley was working on back shoulder throws because he had mastered more than the other two with simpler throws.
Unless you are a player (and not all of them), a coach, or someone in the very closest inner circle... you really have no good basis for judging how good of a practice player any of these guys are.
When the lights have been on, Dobbs has proven he can handle the pressure and lead his team back. He's proven he can manage a game and lead the team on the field. He's proven he can run, extend plays, and give DC's a significant problem to solve running the ball. He's proven he can fairly consistently hit shorter and intermediate throws. He's proven he can win.
What he hasn't proven that is necessary for both him and UT's O to take it to the next level is the ability to throw the ball down field accurately leading WR's.
The competition is pretty much over for now. Dobbs is #1 by a decent margin. Dormady is #2 and it seems that Jones would be very comfortable with him playing. Jones trails by a decent margin. We can't be sure that Jennings would even be the emergency QB at this point.