That would make sense to me. I come from a mountaineer-lite perspective so thinking of how “technical” something is drew me to technique - mostly to avoid “difficulty” which can mean many different things.
foot_scale or something similar seems the best choice, there’s also a mtb_scale in use. pedestrian makes me think more of the walking end of the scale. It sounds a little weird, but everything else I’m thinking of is even weirder.
Technically scrambling isn’t really foot as it uses all four limbs, but scrambling is niche. I would envision people putting whatever technical scale is local alongside it - YDS, BMC, SAC, UAII, etc for more clarification for those that actually care while keeping the key simpler for 99.9% of everyone else. 
If this eventually does get migrated we’d have existing T4-T6 there anyways for more detailed information.
Before attentive_walking existed (which got added due partially to @F_Weinmann’s very detailed post and noticing myself a gap when hiking this summer on trails) surefooted_hiking was just surefooted_walking, but I renamed it to break it away from the two walking levels under T1 in terms of being able to migrate this cleanly.
Some of the ideas around strollers and walking aids and how they impact obstacles are directly from the post mentioned above.