I just want to clarify a few points in didrock’s original post.
We expect that a new theme will take a lot of work to get finished, more work than can be reasonably accomplished in a single 6 month cycle. So the plan of record for 18.04 is a two pronged approach:
First we take the existing Ambiance theme in 17.10 and spend some time getting it in good shape for 18.04. This will need input from you, calling out the things which you think need fixing. We will also spend some time with our design team to get their help as well. As Didier says, this meeting is already scheduled, so please give your feedback on that soon. That’s probably best dealt with in a separate thread though. So, let’s use this one: https://community.ubuntu.com/t/ambiance-gnome-theme-bugbears-and-what-can-be-done-about-them/1637
Meanwhile, we as the community will be working on a new theme. This can be made available to 18.04 users via a package in Universe. If it’s considered “finished” by 18.04 then we can also look to move it in to main. I don’t want to discourage anyone from contributing to the community theme, but it will be a lot of work and is unlikely to get done in 6 months.
Let’s not rush it, let’s get it perfect. And while that happens, let’s get Ambiance smartened up as well.