What if you could “crouch” causing you to make less noise BUT you move slower. I think it could add a small level of stealth. 
I think that someone else has had this idea before , because it’s said that they plan on adding stealth mechanics in the kickstarter.
I hope they do 
Crouching could increase gun accuracy, slighty shorten reload/drawing times and decrease noticeability at the cost of movement speed
Crawling could allow even more stealth at the cost of movement speed and not being able to use anything other than pistols or rifles and would be more useful when they bring in wandering mobs. You could craft camouflage which decreases noticeability all around, and dig shallow pits which basically make you invisible, good for sleeping without having guys show up or start attacking you. Acid rain could start doing damage immediately, until you stand up.