[mst]

> The few times one tries to actually keep a partially covered window (i.e. show only the last few lines of a terminal visible), the UX is terrible because as soon as you switch focus the visibility of the entire stack of windows changes

"pop window to front on focus" is a choice - in fvwm2 by default it doesn't happen, you need to click the window decoration to bring one to the front and can focus it just fine without doing so.

I use focus follows mouse as well so all I have to do is put the cursor over wherever I currently want to type into, but while I personally think the combination of the two is more than the sum of its parts, 'windows stay put Z-order wise' is great on its own too.

> Scrollable tiling managers, however, would be the bee's knees: windows are laid out on an infinitely scrollable horizontal layout, which would also easily replicate the common side-by-side layout "power users" often rely on.

I have a small script called xclus (https://trout.me.uk/X11/xclus) that fires up my xterms pre-tiled and scroll around them - including sometimes borrowing the left hand pair of the screen's worth to the right to end up having six dedicated to a task rather than four. Looks a like https://trout.me.uk/screenshot4.png in practice, look at the pager at the bottom to see the pre-tiled ones that I can scroll across to.