I like the idea very much in general of redesigning what we use as “hiking difficulty”. Still this (on the lower end) for me has the same problem that the current sac_scale has.
For the casual hiker SAC T1 and T2 are too broad, there is a lot of detail within it that we could pull from other tags, but which might also warrant splitting up the values 1 and 2 into further values.
My idea would be something like this (for splitting the Value 1 in your proposal):
Value 1: Easy walking:
Description: The ground is mostly smooth. Very small obstacles might exist, but they are very easily visible, and easily circumnavigated. When walking you need to pay pretty much no attention to the terrain. The path is useable by everyone, including people not that sure of walking and strollers. Might require hiking footwear when the weather is bad.
This would mostly be used on track_type=1 or 2 tracks, or paths that are about NFS class 4 or 5. This is very much on the low end of SAC T1
Value 2: Walking
Description: The ground is slightly rough. There might be some smaller obstacles (bigger rocks within the ground, some overgrowth), but they don’t require a serious effort to circumnavigate. Obstacles aren’t higher than shin height. Keeping a bit of attention to the terrain is important, but taking a look around for a couple of seconds while walking isn’t a problem. Likely not useable by people that are unsure of walking (small toddlers, seniors that require a walking aid), using a stroller is probably not possible. Hiking footwear recommended when the weather is bad.
Typical usage would be track_type=3 or 4, maybe some track_type=5, many smaller forest paths. In NFS classification this is a “wilder” class 4 or a class 3. We are about in the middle of SAC T1.
Value 3: Hiking
Description: The ground is fairly rough. Small obstacles (smaller rocks, overgrowth) appear often/continously and need to navigated. Bigger obstacles up to about knee height might be present, but can still be navigated mostly without stopping to check where to take the next step. Continous attention to the terrain required. Certain amount of surefootedness is required, so smaller children and seniors likely shouldn’t take this path. Terrain might get fairly muddy on bad weather, but hiking gear is recommended in general.
This might get used on some heavily overgrown/low usage tracks with track_type=5. In the NFS system this is class 1-2 with some harder class 3 mixed in. We are still within SAC T1, even though this might start to pass into SAC T2.