Why does this happen? We're not entirely sure. I figure it's probably because there are no teams close to our bracket, but when that happens we usually get an estimated wait time of 'Unavailable'. That's when I know our night is going to be bad and filled with dueling outside of Orgrimmar in between queues. Because of the new matching system, which Drysc said they continually improve, teams are better matched than before. For some, this means longer wait times, although it also looks like they've allowed more concurrent matches for lower brackets. For 2v2, in particular, the most populated bracket, the wait times used to be excruciatingly long. This has changed drastically, which is a good thing. Matches are almost always instantaneous. Almost.
Sometimes, the estimated queue times are still way off. The problem with lying queue times is that it doesn't allow you to do anything in between. It's almost like waiting for the school bus while wanting to hit the loo. You don't want to go because you're thinking the bus will be arriving shortly. You wait and you wait until you finally decide you have time to do No.2, and when you're finally settled on that seat, the school bus honks its horn with your pants down. That's kind of how erroneous estimates are. It doesn't leave you free to do much. So, while I appreciate Blizzard's efforts at making our Arena queues better, I'm still WTB accurate estimates.