With mercurial I think is better to abandon the idea of rewriting history to make it look nicer or more linear. The good point is that your history reflects precisely what happened and how developers merged the code
Rewriting history doesn't just make the git log look nicer. It gives you the ability to more easily create atomic commits, and it ensures that commits in a branch that is later merged back to master are contiguous instead of sprinkled among all of the other commits from all other branches. If you are tracking down a bug, this helps a lot, especially if you use git bisect.