I have a hunch that cruisers knocking out SHW sized guys started happening less when the gloves got bigger.
The evidence points to the size of the glove having very little impact upon the power on delivery. No gloves at all does seem to make a difference.
That could be part of the reason. The other part of the reason could be that changes to the sport finally began to suit size. It became easier and less frowned upon for boxer's to carry weight thanks to new training and dietary practice. Taller fighters can carry the most weight. Shorter rounds. Bigger gloves. More tolerance to holding. Before the biggest giant heavyweights were a wide open target to world class fighters. They probably needed newer methods to get the best out of their bodies.
and yet with wet horse hair gloves the stuffing can be manipulated away from the knuckles. Newer gloves have layers of shock absorbing rubber type foam. Larger gloves do not make it easier to land on target.
You are over analysing things. The likes of Riddick Bowe, Lennox Lewis, the two Kilt brothers would have almost certainly have dominated the division had they been around in those days.
But if they were around in those days they would have been at the mercy of the methods and elements to the sport that favoured lighter fighters. Trainers would have kept their weight down because it was what they believed then. Giants might have burnt out early and developed the wrong kind of techniques reacting to faster smaller men. Out growing their strength. 15 round versions of Lewis, Bowe and the kilts would look different to the over developed behemoths they became.
No matter what once these guys fully matured they will still have been 230lb+, hardly small fighters for those days.
How do you know (without modern training) they would have developed this 230lb corectly? Apart from Carnera (who always was an oddity) guys carrying that kind of weight tended to look less like wlad back then. Even tall ones. Think Jack Doyle, Jess Willard, George Godfrey, buddy Baer, Hein ten Hoff.
All gloves can be manipulated, without exception. No matter what glove is used, "the fighter who lands first often" has a near insurmountable advantage of some description. There just isn't a big difference in terms of how hard you can punch, where professional gloves are concerned, using the available evidence.
Klitschko could not have dominated his own era without a tag team partner or his own house rules that only allows his 'fight' to take place. That's why he had to leave America during his own terrible era. Klittiy is not in the same ball park as Lewis and Bowe.
Modern training, come on then tell me these modern training methods that these fighters were using in the early 90's.
Smaller gloves are an advantage for all fighters in terms of how often you can land cleanly. A smaller fighter versus a giant is already up against it. not being able to land cleanly so often is just making him further disadvantaged than simply being outsized.