Okay, so the short answer of your ask is “no, it isn’t hard”. A normalized and/or linear curve as a baseline would absolutely be great for WoW for a variety of reasons, even paired together
For example, with linear gear power, and gear normalized around normal difficulty as the baseline, you have a content cycle where doing normal in normal nerfs the content and gets you ready for heroic, which is still beneficial for helping players learn. Heroic then drops gear that does the same, for heroic and normal. But since we are linear rather than exponential, the raid tuning can be made much tighter AND normal still gets nerfed, but not necessarily overgeared into a face roll
And then, mythic raiding offers the same items as heroic. The difficulty can be tuned around that fully kitted heroic gear as the normalized baseline, the content itself never gets nerfed due to gear BUT the tuning can be made much tighter and more accurate. The content becomes a prestige, where the reward is visually distinct and optional.
So why DONT we do that?
As it turns out, players have consistently voiced issues with normalization of gear every time they’ve even touched it in the history of the game!
Psychologically, it doesn’t provide them enough of a jump to feel stronger, and that game feel is very important for the majority of players in MMOs
But beyond that, gear also serves as a gap closer, and an exponential gap closer allows for easier content to become MUCH easier, which also translates into a more clear distinction between farmable content versus progression content, which has helped keep raiding from dying out entirely!
They DID try to include a mechanism for working around this via a normalization strategy a la titanforging, but the RNG nature of it made older content not only mandatory, but unlikely to matter and thus busy work
They could fix that by making something like an upgrade track for the expansion, but then that comes with many of the same issues, and removes new carrots for those who enjoy the chase…which is the majority of those who pay the bills
From a TECHNICAL standpoint, we absolutely COULD make such a swap EASILY. From a REALISTIC standpoint, it’s just something that turns off those paying the bills every time it’s happened, and the consumer is voicing their opinion loudly each time and the business adapted accordingly
Unfortunately, it’s very likely WoW will EVER have something like this without it being tacked on, like a new raid difficulty that explicitly scales everyone down to the same downscale AND also tunes around that. But that’s also a system that flies in the face of why we don’t have dynamic mythic raiding anymore (ignoring actual reasons, this is the line fed)
In essence, there IS a lot of upside to what you propose from a MECHANICAL perspective, it just comes with downsides in the form of baggage in the PSYCHOLOGICAL perspective, and adds more overhead for the DESIGN perspective without any real payoff over the current model (at this time)