Me, I'm partially colour blind, and there's one thing in particular in the game that troubles me, and that is, decay on wodden items, when they decay, they turn slightly red, except, in my case, undecayed wooden items and mostly decayed wooden items are indistinguishable from each other, so it makes repairing stuff pretty much guess work.
What I'd like to suggest is a toggleable option that either, highlighst decayed items (wooden expecially) in a really different, distinct colour, say blue for instance, or highlights them like objects behind buildings etc are highlighted. Such a small change would make the game seriously more pleasant for me, and , no doubt, other people who are partly colour blind.