The post-64s used sintered metal frames & stamped parts. By the early 1980s they were back to forged frames & had improved other internal parts to a degree. That was not entirely connected to the introduction of the angle eject feature.
The barrels were not a problem.
I deliberately said there was nothing wrong with the pre-safety non-angle-eject DESIGN.
I didn't say anything about the execution of that design, or the quality drop in post-'64 94s.
My 1951 Model 94 is tight, utterly reliable, and slick.
My later 1990s Model 94 is an angle eject with crossbolt safety & rebounding hammer. It's loose. The overall quality is much better than the immediate post-'64 versions, but not quite up to the '51 carbine.
In looking at the article referenced, it appears one of the engineering changes was relieving the underside of the bolt for a "smoother" (as in less effort required) lever cycling.
This wasn't needed in the older pre-rebounding hammer guns.
The rebounding hammer requires a stronger hammer spring arrangement, which produces more tension on the underside of the bolt from the hammer dragging along it as the bolt travels rearward.
The result of that was a corresponding increase in the amount of force needed to cycle the lever rearward, and a stiffer trigger pull than the original design produced.
My 1990s 94 rebounder has a much stiffer lever throw, and I use the large loop lever on it because of that. Bigger/longer lever loop gives more leverage to counteract the stiffer lever throw.
With the standard lever, that gun takes noticeably more effort to cycle than the older one does.
The new engineering in that respect isn't any kind of improvement over the original DESIGN, it's there to reduce the length of contact between hammer & bolt during rearward travel, which in itself reduces some of the effort required to drag the bolt along over the top of the hammer during cycling.
In other words- it's not an improvement over the original DESIGN, it's a bandaid approach to "correcting" a problem created by the current re-designed actions on new 94s.
In that respect, it's a good idea, but if the people who developed the rebounding hammer modification back in the 1980s had not done so, the new engineering in that area wouldn't be needed. It's a created solution to a created problem that wasn't there when John Browning designed the 94 to begin with.
The round locking bolt trunnions may help, can't say on those.
Otherwise, quality coming out of Miroku is excellent. They are not, however, superior to ALL preceding Model 94s "in every way".
If you want a new one, I'm not trying to talk you out of it.
Just putting things in perspective.