Comment 1 for bug 198084

There was at least a discussion thread that most "preview" style actions like 'diff' and 'missing' would be turned into options on the other commands. So "bzr merge --???" would show you the revisions (aka missing) and you have "bzr merge --preview" instead of using a diff command. (They give slightly different results, because merge --preview actually handles conflicts, etc, diff -rancestor:... only gives you the estimated diff.)

"bzr pull --preview" does seem reasonable. Though does it only give the diff to the WT, does it give a "log" listing?
This is probably better as a feature discussion/blueprint rather than a bug report. Though at least it is tracked somewhere.