It's a long time since I did UX as part of a role so I'm not up with the latest concepts and ideas but I had a couple of personal observations/thoughts after 2 weeks on Cake.
These are purely based on my own opinion and have no qualified basis at all so feel free to ignore them.
I like the new little 'How to' bubbles that have appeared in the last 24 hours, short, to the point and not intrusive.
I'm really enjoying the connection focus on topics and not people, it opens up conversations with people from a far wider variety of backgrounds and viewpoints, political, social, geographical etc than FB generally tends to.
On the 2 main feed pages, Home and For You, I find the individual article headline area a bit busy, I'd go for the main headline font a tiny bit bigger, the headline max characters no more than 2 lines, maybe a slightly larger gap between the title and the next line down and a stronger delineation between articles, which even a few pixels of white space might give.
When posting, the Cancel and Next etc buttons way up in the corner but the rest of Cake is very centered. It's a point of difference to the norm but does interrupt the flow a bit.
I think it was when replying to a article/topic the submit button is above your reply not below which felt a bit odd.
Anyway, loving it and planning on sticking around and spreading the word, You can have your cake and eat it too.