Was MJ making reads on those plays? For some reason I thought they were designed runs.
Anyway, Marshall had a terrible game. No doubt about it. But I wouldn't go benching him just yet. He's shown what he can do before in multiple games, and it's fantastic. At 4-3 (0-2), most of our goals this season our gone -- I want to see Marshall keep playing and learning the offense as a starter so he can ball out next season. If he has another one or two like this, then fine, switch to MJ, but be prepared for the fact that he very well may get beaten out again in the spring and we'll be starting another QB with no experience.
The solution to Marshall's tentativeness may just be playing more. Don't forget, this is only his seventh start.