What should those games be selling to be classified as "exceptionally well"? 100k for Muramasa, and 200k for Senran Kagura? Both had first weeks about as high as the LTD for the original releases on much more successful platforms. You can't really ask for more than that.
It doesn't really matter anyways. They'll continue supporting both the 3DS and Vita, and they've done well on both platforms. Can't really ask much more from Marvelous.