I have feedback for you, and it’s much easier to explain it here than at the jawiki Village Pump as I can upload images effortlessly.
FYI: My preferred appearance is normally set to Vector (Legacy).
On the top right corner, there are a lot of frequently used links, and I see an explanation and its short-cut in a small pop up when I move the cursor over on one of those links.
For existing users, we probably don’t read the pop up to locate which link we want. For instance, I look for the word "ウォッチリスト” for the watchlist when I need to visit my watchlist and just click it before the small explanation pop-up would show up. (Sorry, but the cursor itself is not showing up on the image.)
When I see the new version, now the word "ウォッチリスト” (Watchlist) is replaced by an icon. When I move my cursor over it, I see the explanation “変更をウオッチしているページの一覧 [Alt+Shift+I]” (The list of pages you are monitoring for changes [Alt+Shift+I]) in a pop-up as well. However, It does not register into my brain immediately that the icon is for the Watchlist because my brain is looking for the familiar word "ウォッチリスト” (Watchlist) .
Once again, this is a relevant comment only for existing Vector users (or could be just me), and it might be different for new users.