The way I see it, the only time a longer bolt handle makes a difference in effort, is while rotating it. You could have a bolt handle six inches long and it doesn't make a bit of difference when chambering, or ejecting a round. There's no 'leverage' involved. My 43, that was made in the worst of the war time, operates exactly like my 53, smooth. Both are smoother than either my .22 Marlin, or my .22 Mossberg WMR. Saying that it's a bad design is nonsense, IMHO. But, you're entitled to yours.
yet again, I am not saying it is a bad design, I'm saying it's a crude design. you are also comparing a centerfire design to a rimfire, two totally different sets of requirements for construction. if you ended up with smooth actioned mosins then good for you, but you need to understand that they are the exception, not the rule.
and there is leverage while cycling a round, rotating the bolt handle upward 90 degrees is the action that cocks the rifle and no matter how you want to look at it, you exert leverage when lifting while cams force the firing pin back and lock it to the rear. that is the only time you need leverage so yes when chambering and ejecting you don't need the longer handle but during cocking there is a serious need of a longer handle.
look at just about any discussion involving the mosin nagant and you will see countless people tell you that it requires the shooter to slap the handle upward with their palm to apply the necessary force to reliably chamber a new round, there isn't a person alive that will tell you that this is necessary for a springfield, enfield, mauser, arisaka, carcano or any other rifle from that time period.