Yes there is. Ask anyone who plays both rbgs and arena at a high level. it is much more gratifying to win a challenging rbg.
You can argue that it's because you put more time into the game, but it doesn't feel that way for me personally. If the community wasn't such a detriment, more people would realize this. I'm hopeful for wod, because most of the problems brought up in this thread are due to the players, rather than the actual bracket. If people either learn to play fair or blizzard fixes a few bugs, we could see the same levels of participation we've missed since cataclysm.
Well, last season was long, and participation in 10v10 always tapers as seasons stagnate. There were points at the end of last season where three or fewer teams were queueing, all exploit teams and dodging each other. The bracket definitely has its lows but this is only because of the barriers to entry when participation is dead- it's hard to make groups and the only people left want to cheat for easy rating,