I'm well beyond "middle-age" (unless you know anyone 124 years old...), but I know of the kind of bike of which the OP speaks. I refer to such bikes as "geezer-fied", and alas, it seems to be an epidemic in my area. My "WTF am I gonna do with this" pile is overflowing with upright bars/stems removed from once very nimble roadies, now waiting to be set free once again.
As for long+short vs short+long, the elephant in the room is body proportion. Neither is "better", but one is "better for you", based on which one favors your proportion of leg length vs. torso length. There are, of course, many other nuances/factors, such as level of flexibility, arm length, etc., but overall, leg/torso proportion is a good place to start when thinking of ST/TT proportion.