Facebook already includes tools to solve your issues. Either unfriend the vague acquintances, hide all their posts from your feed, or hide the annoying posts following some criteria.
I "unsubscribed" from the family member I no longer want to hear from. That way we're still "friends", I can visit his page and read what he's been posting, but it doesn't show up on my feed.
Agree. Facebook is a tool whose scope of use can be adjusted by each user's needs and expectations. It is true that the setting changes are not the most user-friendly / intuitive. It's also fair that some people want to cut off certain dependency of any tool, but it's not the tool to blame but a personal choice to make.
Actually, I just discovered that ads keep appearing even if you defriend the person!
I just defriended someone who works for a social game company because they were pushing waaaay too many ads through to my feed. I felt bad about doing it because I don't mind the guy on a personal level, but shit it was annoying. Anyway, having defriended him I reloaded my news feed only to find that the ad was still there!
Now, maybe that's a one-off and the servers hadn't quite synchronized yet, but damn. Facebook makes me dump my friends to avoid ads and still gives me the ads!