I'm pretty sure we've been asking for 2 DA stacks since the ShB rework, but I do quite like the Oblation idea!
if anything, I wish the devs would nerf the potencies on Edge/Flood so that we could be allowed to generate a lot of mana again.
maybe allow Dark Arts to change Flood into Dark Passanger and Edge into Power Slash (no idea why those animations were tossed aside, they're still as magnificent as I remember)