I'm new to steemit and still don't know how a lot of this stuff works. Something that would prevent malicious downvotes from completely ruining a post is a great idea.
It would be great if people had to explain why they downvoted. A post should only be downvoted if it is racist, spam, plagiarism, etc. Simply not liking someone's point of view is no reason to downvote.
Don't worry. As long as you don't do something that is far away from common sense like writing a psot with extensive cursing and live threats, extensive plagiarism (pretending stolen content is your own), or excessive spam - especially "follow for follow", you should be save from downvotes.
Most downvoters also give comments. they are also people you can talk with.