Paying 7 and even 3 for a a card that costs is terrible.
Assuming that I would have 5 counters, or more damaging monster out is flawed. If you should be countering or doing more damage as you say the deck would never win.
I've played it using pestal and swallow, neither kept up in the arena. The AI always drops at least 3 shards by t2, I cannot steal them all or swallow them in the same amount of time. Assuming of course I draw those cards to the 10 shards in the AI's deck.
It's like you are saying that Rain of Fire and Explosion are too strong because you can't defeat Eternal Phoenix (the false god) with a RoL/Hope or a New old Times deck. (For record: I am not saying that shard of freedom is fine, I am just saying that your argumentation is wrong. 1. neiter pestal nor swallow nor SoSac decks should be able to defeat every deck in platin. 2. Don't take the gold and platin arenas into acount too much. the thing that should really be in balance should be pvp and pvp2.)
As far as in pvp, having a card that cost and produces more damage, momentum, and essentially immaterial is silly. I'd be fine if the evading was removed. Quinessence and shard of wisdom cost more and together do essentially less what this shard does for .
Quintessence+Shard of Wisdom is something that makes imune from anything but 2 shields which aren't used too often. Also, you probably won't use quintessence anyway, because you use either creatures which are imortal already, or you use it with Anubis (well not often) or the aether nymph.
--> Further, in a pvp deck, you can only have 6 of these shards in your deck. Taking into acount, that with 2 shards out, it starts to get difficult, and with 3 shards, it gets silly to defeat this decks without some nice mass-CC, it probably really is a bit too strong.
A question, primarily to people who are creative deck builders.
1. If SoFr is used in a deck, ever made and played with a deck that has less than 5 of them inside? (All that I can say and have tested is that a Mono Air rush becomes a pretty average deck all of the sudden if there are only 4 SoFr in it.)