I don't think I ever actually got an answer to this question when I asked it.
Would full removal of Marble Phantasm be an appropriate nerf of the current OS Arcueid for Oath Siberia? Would it be enough to make her non-bullshit?
Since it would really just be 'monster with huge melee potential, nothing else'.
http://s1290.photobucket.com/user/zansnul/media/6dad42dfddf5e307b9a445242f420a55_zpsmsb07xzj.jpg.html
Do note, this is uncut version. I cut the image a little to make it fit better as avatar.