Agility of ships is not a simple thing to do - even if ships have same maneuverability values in shiparch.ini, they still handle in a different way. So each ship will need testing, and without testing I cannot guarantee any results of ship handling changes.
I agree that Rheinland Bomber must be significantly less agile than Titan - it's a unique ship that was made for taking out battleships, so it should be vulnerable against a normal vheavy fighter.
