I would like tab islands to show as a horizontal strip in vertical tab mode, rather than a named dedicated tab like they do (vertically) when tabs are horizontal, and the option when I hover the tab bar for ~3 seconds to temporarily expand to show names (as an overlay, not a proper expansion which would cause a layout shift on opened webpages), among other improvements to the feature. Such as a compact mod, with less padding around the favicons, and shrink the girth of the bar as a whole (I use them icon-only). Custom Favicons for pinned tabs would be nice too, but meh.