Why not keep a 5 seat assembly, and make the lieutenant governor a separate position? Like in real life Virginia. We'd have a Governor/Lieutinant Governor that acts like President/Vice President of the region; except they'd be elected separately.
the difficulty, of course, is making the lieutenant governorship a meaningful position. 
We can give the Lt. Governor all the bad chores, like updating the wiki and running elections, since we can't have a CJO that will do so and giving election-running powers to an appointed-for-life Associate Justice in Nyman is a recipe for disaster.
I prefer to have the Lt. Governor come from the Assembly, like in the Northeast, though. I don't want to create too many offices.
My proposal would only create 1 new office.
