The Uncanny Avengers team, as seen on the cover for their first issue, and the lead title for the Marvel NOW! Relaunch are white., Very white. Sure, one is an Asgardian, but that's hardly helping their case. The best you can go with is that the Scarlet Witch is Romany… meanwhile The Red Skull, evil Nazi under Adolf Hitler, has a team that look a little more genetically diverse. Even if that means two of them have animal heads.
When the Justice League #1 rebooted as the lead book for DC New 52, the team had one black man.
With Uncanny Avengers #1, merging the X-Men and Avengers teams have given the publisher a larger cast to choose from, especially given the more diverse X-books with prominent characters including Storm, Bishop, Sunspot, M, Angel, Frenzy, Cloak, Maggot and more. But they haven't taken it. Sadly "Canadian-American" doesn't count.
Jonthan Hickman has promised an 18-strong Avengers team, and it's likely that will be a lot more ethnically diverse, indeed it may be a counter book to Uncanny Avengers in this regard. And no doubt future issues of the new series will mix it up as well. But for the premiere launch title, cover, and cast, some may find this a little disappointing.