Why are you talking about a situation without admins? I don't know where you got this from.
Your proposal to make almost everyone admins is effectively a proposal to remove admins.
OK, maybe you don't know this yet, but all changes in MediaWiki can be undone. There is no such thing as permanent damage.
You can't revert bad press, or hurting someone's feelings, or someone leaving Wikipedia because of stress, etc. There is definitely such a thing as permanent damage.