Personally, I would prefer that the Teutonic Order get fully integrated into the Prussian Empire Orbat. They don't play any differently to the Prussians in any way and only have four special units that the Prussians do not have any access to. The rest is made up of standard Prussian units and the two biggest models the Teutonic Order has, the Prussians already have access to. Which defeats the purpose of their existence.
The Teutonic Order, other than in the fluff, has lost any relevance to the game it had once the Hochmeister was given to both them and the Prussian Empire.
Something has to give, and since its apparently a "bad idea" to remove the Dreadbot and Metzger from the Prussian Empire Orbat, the next best thing is to just fold the Teutonic Order into the Prussian Empire like the Belgians were folded into the French Orbat.