Yes, it seems to have reached a point where adding improvements will be only for some tiny cosmetic details. Let's say, I appreciate when the lines surrounding fields have a smooth look, with more than 1 pixel thick. I think it looks nicer. Perhaps would you want to switch your profile to the old default theme to compare both somehow, or I could do it, with two windows, and make a screenshot of each side by side.
But, there is no hurry, whereas I'm in the middle of a big prep to do this month, for some events.
Meanwhile, if you find things of interest to share, I would gladly read from you on the forums!
(I have put up the pieces of a machine for someone, and right now heard about the HWE, and I'm pretty excited because it will solve an issue I was foreseeing! - https://wiki.ubuntu.com/Kernel/LTSEnablementStack