I also vote to bring them back.
They dont need to be set a million times, if they arent set right the first time, give the ball to the opposing team.
They cant result in penalty athons because they are differentials (though i think the differential should be replaced with a handover as was succesfully trialled a few, well actually many now, seasons back).
The biggest thing about a contested scrum is that they can turn matches and make the game more flowing and attacking. Wingers must drop back to protect the ball from being kicked into touch (because it often means losing possession). This takes defenders out of the line and encourages attacking football. Players are not afraid to try offloads and flickpasses because dropping the ball and making one error is not always as costly as it is currently.
Even big fat slow lumbering forwards (not that i think they will appear) are not as bad as it would seem. They open the game up for the slower more mobile players to target and run around, particularly late in the game, much like the lack of interchange used to.