I was disappointed that once a window is broken, either you have to replace it with a similarly fragile window or you just board it up.
What I’d like to see is the option of sturdy shutters that can be built at a slightly higher Construction skill. These would function like windows but by default not allow light through (no curtains necessary to block vision). This would allow passage through the window while also providing some protection from enemies.
The recipe could be a simple 6 2x4s, some nails, and a hammer or equivilent.
(As a sidenote, it might be interesting to add a ‘hinge’ recipe using scrap metal/steel for use in creating doors and shutters. On the one hand I dunno if it’s worth getting particularly finnicky with recipes, but on the other hand it makes sense)