Lyxen
Great Old One
Honestly, any advice that pushes a playstyle before the group has found its preferred playstyle is a problem. Railroads are fine, for people who like them. Similarly, sandboxes are fine, for those who like them. Put a player who isn't suited for them in either, and it isn't fun.
The last point is very true, I've seen a very experienced group totally at a loss when dropped in a complete sandbox by surprise, and not enjoying the situation at all. They just preferred having a compromise where, while still having lots of freedom, they were pursuing epic goals, so when deprived of those, they simply could not agree about what to do, in particular as a group, to continue having the kind of adventures that they liked.