I think it's a response to the difficulty in Nioh 2, which I assume they felt was a bit too hardcore, so they made this more accessible.
To be honest its likely more a response to Stranger Of Paradise which went from relatively easy outside of a couple of fights in a NG, to insanely unforgiving in the NG+ cycles to the extent that even pretty hardcore streamers like Fightin Cowboy dropped the game because it was so unfair.
Nioh 2 had by far the smoothest curve in terms of overall difficulty scaling, although it was by far the most demanding in terms of build crafting because basically no single buff or debuff was ever strong enough by itself, and required the player to have multiple in effect simultaneously to reach peak performance.
Nioh 1 on the other hand was a pretty rough road as they were learning as they went how to handle what amounts to a year-long live service structure. Not sure whether people remember this or not, but on that game with the launch of DLC 1 they had to hard cap level limits for NG+, refunding players above that cap all their Amrita (souls) back in order to pull it back into line. They also had to meticulously block a whole list of exploity techniques which is why if you look back at build guides for that game, very few of them actually work today.
This is the defining difference between the TN games and FROM's stuff; These are basically live-service games that are done ethically. Up front you know that there will be 3 major DLC drops, each one of which will add a set of new missions and a higher difficulty and gear itemization tier. Somewhere along the way they'll also add a final mega-dungeon (999 floors in Nioh and Stranger, 100+33 in Nioh 2) which serves as the proper end-game grind.
Nioh and Nioh 2 also modify level populations on the main campaign as DLC adds new enemy types, although what they tend to do is basically end up with essentially 2 layouts that alternate between NG+ cycles. Its basically why I feel comfortable in dropping the cash on the season pass day#1 because I know that they'll add a ton of new stuff.
On the other hand, waiting a year for the season to finish and getting it all-in-one (usually on sale at that point) could be the right move for you, because by then you'll get the best version at the lowest price; and frankly by the end-game of that the difficulty will stress you no matter how good you are!