I love the FB position and think it is under utilized in todays game. The FB doesn't have to be compact as someone put it, Darrell Johnston came in at 6'2" and 242 according to espn stats.
What you need though is to utilize him. A FB in todays game needs to be an open field blocker, in line blocker, a battering ram, a short yardage running back, a tight end, and be smart enough to pick up the blitz so you can rest the smaller quicker backs that are the way the game is turning.
Some team will find that player soon, and use him at FB, and the whole copy cat league will follow just like it has for a long time. It is just going to take the right person to end up with the right Offense Coordinator, and I think the FB will return with a vengeance.
IMO, soon a good OC will use a FB and several quick backs instead of a bell cow back because there aren't enough bell cows.
Just like the NFL is turning to the more mobile QBs and using them as another weapon, instead of teaching highly accurate timing or reading and pocket passing.
This turning to more mobile QBs is only working because of all the new rules keeping you from hitting the QB. The old school would just hit the QB every play regardless and try to take out their best player.
Some teams, no so much Dallas, are actually looking at their teams strength and trying to build offenses and defenses around the players, and not the coaching style. Example DQ.
Other teams are trying to get the players to conform to what they know.
Both styles work.