And then you get the various 2t Trials Bike Engines - most of which are quite oversquare.
Yet, they are Torque / soft(er) power oriented.
Optimal bore and stroke - it depends on a designers particular 'bent'. And each and every bloody one would argue furiously for their 'optimal' ratio.
Maico 250s, for a few decades, have had the 67 / 70 bore and stroke. My 320s had 76 x 70. When they had 72 stroke, and abandoned it, I have no idea. They may have 'pioneered' it, but they sure didn't stick with it.
Maicos fabled 490 /500 engines, were never a square design - both being a slightly oversquare engine. I think the one '500' that I know of, with a 'square' engine, is the KX500, at 84 x 84. Though, I'd not be surprised to be informed of other '500s' that are square engines.
Open Class 2t MXers, had such a surfiet of power and torque for their times, they were bouncing around with inumerable bore stroke ratios, when they were common.
4ts keep going for more and more revs, for getting their HP. So, more and more oversquare.
The 2t design, is so interweaved within itself - bore / stroke / crankcase volume / porting as making up the whole induction, and exhaust cycles, as to be incredibly varied in how it's done.
Someone coming out with "this is optimum", I just think of as one who has picked his 'favourite' - or, is subscribing to their particular worship of a designer / brand / model.
There is quite some arguement that 2ts will go to more oversquare engines, especially with such techs as DFI, as the fuel component of the charge, will be less dependent on the 'whole engine' concept.
I think, for quite some time, the Evinrude E tech outboards have been based on a fairly oversquare ratio. It seems to be 96mm x 76mm for the V6s, and 91 x 66 with the V4s and inline engines. Of course, these engines are used in a much different context.