You can narrow/widen them individually, but it's always a bit of pain to have to access the somewhat buggy Track Manager, simply to hide a track.
I would love to simply right click a channel strip and select a 'hide' option.
For unhiding, then you would have to resort to Track Manager, but for unhiding sequential blocks of tracks, simply click & drag across 2 visible tracks and select 'unhide hidden range' or something like that.
Regarding sends, I think the way forward is to have all the controls relating to sends on a flyout, similar to the PC EQ, but a good deal smaller, and when this is not being displayed, the send is simply a one line text box with the flyout icon
This way you could easily fit 6 sends in the existing 1 space module