1st you should hire someone from bioware or bethesda(or something) to rewrite your story missions and give players to start over story wise or continue on ect.
Order specific abillity you can unlock once you pick a order. The abillity is different for each order, Order of Whispers,Vigil and Drumand Priory.
Have a unlockable abillity that is different for each species you pick during the story.