When is the new design coming?
When is the new doulingo web design coming? (to old users)
Patience is the best advice I could give at the moment.
I wouldn't be too quick to ask for the new layout while it is still being tested. The new design is still missing several features, such as the Vocabulary tab. The sentence discussions just returned after not being available, and there are still a lot of discussion formatting that folks can't do, like numbered lists. The special courses added for Christmas are also not available, neither is there the option to gift lingots to other people.
There are good things about the new format. And the new people who are automatically being put into the test group won't miss what they've never had. But, if you've been here a while, you might. Meanwhile, if you wait and DL decides to go with the new layout, you'll have the benefit of getting to it after we've finished a gazillion bug reports and feature requests (and sent in a lot of praise that is due for the awesome and hardworking design team.)