I'd also really like to see a mod like this in KCD2.
What is needed: Not only basic modding capabilities but also knowledge of lua-scripts.
Possible problems: Not only hunger, fatigue and energy, but also Mutt's obedience in KCD1's timescale mod didn't adjust to a new timescale properly iirc.
Also, in other open-world RPGs timescale mods can break timed quests - and KCD also has time sensitive quests, so we have to keep that in mind when looking for bugs/glitches caused by a mod like this.