tl;dr version: I made a userscript that forces the new Gmail interface to show the email list as the expanded 3-line-per-thread display. You can find the userscript on my GitHub gist.
Although I don't use it for my personal Gmail account, I have long used the 'Split Pane' visual mode (with a vertical split) for my work Gmail. I find it easier to go through a lot of email by having the list of email threads on the left, and the currently selected email thread showing on the right.
However, with the recent Gmail interface changes that landed around … Read more →