I actually really like how Shape Up make you think and question the whole notion of having something in the first place. In this case a roadmap and backlog.

Having a roadmap (I like your "strategic direction on a timeline" description) could potentially introduce cognotive bias in the team's shorter term decision making. The value of a backlog is actually also very questionable. Just because something was raised as something we should do at some point, doesn't mean it still needs doing ... and having an often very large backlog makes it harder to see potentially much more important stuff.

A go-to thinker (for me at least) who makes you re-evaluate things which many just take for granted is Kent, one of the 17 people behind the Agile Manifesto. Check out this interview with Kent if you have some time. In it he talks about things like why he voted against the name "Agile" and his valid critical thoughts on the whole commercialisation of "Scrum" > https://www.firsthuman.com/podcast/23-leaving-facebook-with-kent-beck/