Yeah, nobody wants to deal with vandalism on their main page. If nobody notices it and changes it (for example, noone is online), it can be incredibly damaging to the wiki's reputation. In my opinion, all main pages should be, at the very least, autoconfirmed protected. Templates do not matter as much, but cascading protection on the main page is a good idea.
Oh, and all policy pages should be protected. We can't have normal-level users (even those with good intentions) changing policies. They require discussion to change.