The buff it needs is:
-2/-3 cost
+1/+2 Health
-15? cost in Bazaar
Don't think we should buff its Health, at least not above a Grav shield would stop (Well, its petty sad.)
Though 6 cost for 4 attack (Or 7 for 5), seems immortal, but still stop before a shield, are too weak.
IMO their only use are Oracle counter FG or to bare SoWis (For the later, I even prefer unuped Immortal over Elite, just because the cost.)