1) A drain is not a guaranteed cost. There are many ways to time
production to avoid to cheat such a cost.
2) The primary concern is nova + sofo then activating the ability. In this case the ability only costs 2
with a gravity mark.
1) There are many ways to time the play of any cards, in order to maximize their utility. The advantage gained thereby is a reward for good play. This sounds a little too close to a problem with playing well, rather than with SoF specifically.
2) The primary concern is nova + sofo then activating the ability. In this case the ability only costs 2

with a gravity mark;
which is 2
more than it is now. Isn't that a reasonable place to start making changes, in small increments?
I may be biased, however - I voted that it's fine how it is. Even still, were jawdirk's suggestion imposed, I wouldn't mind it at all. It fits thematically; the BH is paid for by the drained

; and mono-

gains the benefit of using SoF in essentially the same form as it is now.