I wasn't planning on writing more on this matter. I've already written too much & by evidence of only a few other comments, no one has a strong preference.
Oki Andrew, but I still ask why this may be useful ... you try to keep this functionality, but how many times you find this useful, to just rotate a map with disabled GPS?
To save phone power I have GPS disabled by default, and only enable it when recording my track. And only then for noteworthy tracks. So, with all my route planning the GPS is generally disabled, which therefore means the compass is disabled when trying to orientate the map. Probably an atypical user.
My main point: it just seems counterintuitive to me, to intentionally prevent the user from enabling compass/ rotation behavior.
You never had a problem that you tried to look along the navigated route a few km forward and map still rotated under fingers? I have this issue almost always 
No. I would simply tap to disable rotation. My suggestion is to auto-disable rotation when map is panned by the user, but not to prevent tap to enable.