I am guessing there is an argument to be made for a longer, lower top tube resulting in a lower center of gravity and more standover room. My 1990 Schwinn High Plains has similar geometry, with a long top tube and relatively short head tube, and I do appreciate not having to lean the bike much to get on it when it's full loaded. My Miyata 610, however, is at about the minimum standover clearance for myself, and if I have two full panniers on the back, it can want to "flop" pretty hard if I lean it a bit to throw a leg over it.

Here it is minus the front rack. Interestingly enough, with the stem, saddle height and bars, the fit is nearly identical to my 610, just with a lower top tube. Reach and handlebar height are about the same.