No 10-second run off: I hate these goofy clock rules that only apply at certain times of the game and only if your team is losing. Any conditional rule is stupid. No 10-second runoffs. Ever.
You really, really have not thought this through.
Yes, I really have. This is a newer rule, it was not needed for 80 years.
So what if a defensive lineman jumps offsides to stop the clock? So what? The offense gets 5 yards just like any other time in the game. I suppose all you guys think there should be a 10-second runoff for fouls committed at the end of basketball games as well.
There's 15 seconds left and you're down by 1. You have no timeouts. You complete a 40 yard pass down to the opposing team's 10 yard line. The WR who caught the pass and another WR line up real quick as the center and QB and spike the ball to stop the clock (the entire rest of the offense is still 40 yards upfield). They take the 5 yard illegal formation penalty and kick the game winning field goal, even though they never would have been able to stop the clock properly.
More simply, the QB and center could do the same thing at any point without having to wait for the rest of the offense to line up. Or the line could lineup without the QB and commit a false start. Or the offense could commit an illegal substitution penalty, or a sideline infraction, or any number of other penalties that stop the clock instantly in exchange for 5 yards.
It didn't used to be a rule because coaches were notoriously uncreative and unwilling to use holes in the rules. That has changed in recent times with things like Wisconsin intentionally going offsides on the kickoff to run time and, more aptly, Ohio State using one of the scenarios above to win a game when there was no 10 second runoff in college football (it was added soon after that game).
Additionally you have intentional grounding, which should penalize a team against the clock at the end of a game as a sack would.
ETA: Even simpler, the WR catching the pass simply spikes the ball or throws it into the stands, which results in an instant delay of game penalty and stops the clock. That essentially gives the offense unlimited timeouts at the end of the game.