It sounds like this Tournament will be something that PvP Enthusiasts will want to watch with interest. The entrance fee should ensure that most of the field is made of dedicated players, or at least players who are somewhat sure of their ability, and the establishment of pre-made characters to ensure a "level" playing field should definitely lead to some exciting matches in which we'll see how differences in skill can make or break an arena match. However, It may also bring to light class and talent discrepancies as we watch which team make-ups rise to the top and which fall. Since we already know that additional class changes will be coming to 2.4.0, we certainly have to wonder if Blizzard will try to make some last minute class adjustments to this patch in preparation for this tournament, or if they'll use data from this tournament in making further decisions on class balance.
But either way, if you fancy yourself to be pretty decent at 3v3 Arena play and think you're willing to part with a bit of money to try and win a lot MORE money, it sounds like you'll want to keep an eye out for the sign-ups for this.