Our Jeld-Wen stained wood door is 42" wide by 8' high. It's an archtop within a 78" wide archtop frame with side lights. Our ceilings are 9'.

As a short person with proportionally short arms, I think it'd be hard to reach /open a door that wide.

We do quite a number of 42" x 8'. This is a picture of an alder 48"x8' we did quite a few years ago [4.0x8.0 front door[(https://www.houzz.com/photos/two-rivers-custom-home-portland-phvw-vp~16778200). They do feel a bit more substantial, but that can also be controlled by the wood selection if you are doing a wood door. In addition, as long as you use heavy duty hinges, you shouldn't have any long term issues with sagging.

Have your cake and eat it too by going with an old-timey vestibule. We have one in our Victorian and it's great, especially now that it's winter. The outer entry is nice, broad, and substantial, with double doors and a transom over top (and no sidelights), and then the inner door is a standard-sized single door with a transom (still no sidelights). Outer doors can optionally be left open, and fold into the sides of the vestibule to visually disappear (I do this when I'm hosting and expecting guests).

I just think a 4' wide exterior door is going to be kinda heavy and awkward to swing, and at 8' tall, look kinda squat (it has a 1:2 width:height ratio, while a standard 32" x 80" door is 1:2.5).

As a tall person with proportionally long arms, I think it'd be hard to reach /open a door that wide.

Thank you all for the insights!

Absolutely love my 42" x 8'.