Hey Bill, what decision did you arrive at for these doors? Would love to see some pictures!

Hi Leah. As you like timber what about using a decorative timber screen to fit that space? Enough decoration to give privacy, but open enough so light can come through. Kind of like a picture that draws your eye rather than an ugly square of glass. I'm sure houzz has an article showing these decorative screens in various styles. I have some typical geometrical chinese wooden windows in mind, but I'm sure you could find some laser cut specialist to do your design in metal, or a carpenter to do it in wood.

I used to have tiled floors at the old place ..the whole downstairs was tiled ( lounge, study, living room , kitchen, laundry) terracotta ones..not cold at all contrary to what people think .. the kids loved riding their trikes around the house as it was massive open living space 36 squares in all. we had a wool rug where the living area was so kids can lounge around.. I find tiles are easier to maintain than floor boards.A quick vacuum and mop is all it needed and it hid the dirt well..whereas floor boards collects dust and hair etc.. Timber floorboards are nice to look at..the floating /laminate looks cheap and nasty I'd rather tiles instead.

Budget? Glass is expensive, looks great in certain contexts but similarly can be not that great considering the cost unless it's done super well. In your case because you have a 4m high drop you'd need a handrail either way. Unless it's consistent with the rest of the design/finishes probably other options arguably a more appropriate balance. Define your needs/function and balance the options to a viable cost. I'd agree with oklouise, something along the lines of existing updated to code probably the best balance for aesthetic, function, maintenance and cost.