Others may disagree but I like the idea of preventing repeated use on the same creature... on general grounds of cheapness...
ok granted thats not a true term but I think most understand what I mean.
That said, I don't think this shard should be on top of the list of nerfs. True, this isn't the first time nerfing SoR has come up... I myself argued in favor of it at great length, and I still think a small nerf may be in order... But it seems the general consensus is to leave it alone. Namely because, for the most part, its not really that OP.
As annoying and cheap as instosis can be (and maybe other possible spam abuses) its use seems to be infrequent enough that it is not of game breaking OP-ness. Aside from a deck built around spamming the shard repeatedly it really won't provide much benefit of using a spell equivalent.
Think card advantage... Instant skill use takes SoR + Creature w/ skill -> 2 cards for 2 uses. The same as casting a spell twice. Quanta Cost wise there generally isn't much of a gain here either since creature cost often matches or exceeds the ability cost, and the abilities costs themselves (mitosis exempted) are generally on par with the shard cost ( 3
~ 1
)
In short, the only way for this card to be broken is when it is abused by combining repeated chain usage in conjunction with high cost abilities (namely mitosis thus far).
In my opinion (spam abuse aside), SoR is one of the better behaved and balanced shards. The only nerf that's really justified is preventing it from being used on the exact same card multiple times in a single turn.
More importantly, I think there are other cards out there in more dire need of balancing work *cough* Shard of Focus *cough*