I very much enjoy the ability to upgrade gear with crests, but the changes to how they are earned in TWW make me wonder if I have incorrectly assumed what they are designed to accomplish. To start, my question assumes two facts are understood: 1.) M+ was changed to have essentially two separate target audiences. One focused on running what we are apparently to consider lower keys (KSM to portal crowd). This would include MOST players (I believe this is what we are meant to assume). One would include players looking for an elite challenge - 12+.
2.) Completing keys in the 9-10 range is the pinnacle of the PVE experience in that game mode - we assume this because any content above a 10 grants no additional player power. Progress beyond this grants the same rewards as a 10.
IF these assumptions are correct, the rewarding of the most advanced level crests at a 9 and 10 is confusing. I would assume crests are to be used to upgrade gear to assist in a player gaining power to be better able to achieve their season goals. This reasoning fits very well with a players progress that only raids - they begin to receive these upgrade items on the last two bosses in the raid, and from each boss in the mythic raid. Unquestionably the difficulty of an early boss on mythic in the raid is much lower than the later bosses, but players are granted these upgrade items to build power through the raid to be better able to accomplish their seasonal goal.
As an aside, the raid also has a self nerfing mechanic to assist players in accomplishing their goals, m+ doesnt have this.
This is completely different for m+ focused players. They cannot access this power increase until they are running 9-10s. If our earlier assumptions are correct, this essentially means they cannot access the power increase items until they have already reached the point where they can accomplish their seasonal goal without them. This would be true for all players absent those who are running those 12+ keys, which we are to assume is a fairly small portion of the player base.
The closest parallel we could use to a raid reward system would be if mythic raid only dropped the highest level crests from the final two bosses. I think at that point we would all agree that power increase would not assist players significantly in accomplishing their seasonal goals, and the power increase would be largely cosmetic, not functional.
I wonder if perhaps the reward system in M+ does not currently match the design structure for how we assume players approach that pve experience?
If crests are not designed to grant player power in accordance with the goals of players focusing on that pve game mode, and are instead just a cosmetic power reward, the current system is likely working exactly as it should in M+ - but that most likely makes M+ a much less desirable mode for most players.