@ChrisBrejon certainly a reasonable questions to ask.
However, in my opinion, too many options is a bad idea. We already have enough to contend with by trying to accommodate different rendering intents.
RED IPP2 also provides 4 contrast options and 4 R options - but I rarely hear anybody say “I used IPP2 with low contrast and R4 Very Soft”. Instead, they just say “it’s IPP2”. So if anyone is using anything other than the default, this can cause problems.
Also, we’re not prohibiting people from adjusting contrast, just not doing it with the reference rendering. Anyone can, and always has been able to, establish an “always on” LMT that boosts or lowers contrast of the default rendering to their liking.
There have certainly been requests that whatever becomes ACES 2.0 we ship a library of “look” LUTs via LMT akin to RED’s Creative LUT Kit, ARRI’s Look Library APP, or Sony’s Cine LUTs. Doing so would service people who just want presets and also demonstrate that the base rendering does not restrict from changing the look creatively.
Back to tone scale design: We don’t want things to go unrendered, but I do believe that taking just a bit off our current tone scale midslope and highlight rolloff might help us with reducing the obviousness of some of the objectionable skews or artifacts that are accentuated through the current structure.
I think the key idea is, that we need to identify the behavior we expect from the tone mapper across different displays and use cases, and make sure that whatever model we choose meets those needs. It is easier to discuss this in a B&W context and leave color out of it for the time being. I’m working on talking more on this in a separate post…