User blog comment:Kogath/Monster Hunter: World Discussion/@comment-25083735-20200207000916/@comment-4370375-20200207212146

Ya'll do realize that innovations that start in the new world are not necessarily going to stay exclusive to it right? It is entirely possible that they'll be adopted by the old world and very likely considering how quickly innovations get adopted across the world in real life.

Like not wanting the slinger/clutch claw or mantles I can somewhat understand, even though I didn't even bother with getting some of them until I actually had to because of quest chains and likewise don't bother with tenderizing at all, but the blademaster/gunner divide was at best arbitrary and made half the armors available useless if you only use weapons of one class exclusively which was very likely in the old games because you had to make completely new armor sets for both blademaster and gunner and the latter class had poorer defense than the former.

Hell, the in-universs reason for the desegregation of Blademaster and Gunner Armor was because the Second Fleet Master was of a similar opinion towards the divide.