I think a submission match should be between two faces. It can be very predictable unless it's a screwy finish. As for an iron man match. It has to be between two guys who can go and keep the fans interested. I always thought Ziggler and Del Rio should've had an iron man match at SummerSlam or at least to culminate their feud. I BELIEVE the last iron man match was between Orton and Cena.
A submission match is just something you could even have on a raw or smackdown just too even spice it up a bit, but I see no reason why say punk vs del rio or even cena vs del rio on PPV couldn't be a submission match instead of the standard singles.
Well they don't seem to care what the audience wants anymore so all the more reason to have a 60-minute iron man match but nah I was thinking even a 20-30 minute iron man, or even a submission only 30 minute iron man you know, utilise the tools that are already in place, submission matches are as pg as it gets, use them.