(Yes I've read the Oracle, but I don't want to open 4-7 topic for the same nerf idea). There would be a picture of SoFo, SoV, but I'll go through all of the shards, so just in order.
First, SoSac has a nerf in the Arena:
The AI only plays only 6 per game. As I know it was in the 1.3 patch, after a little when shards came into metagame. In that time, the shard cost was
, so it was more in mono (in the most of cases) and less in Rainbow. Now they are more useful, cheaper and faster in mono, so the decks relying on them are better. And with Dexterity some of the gives too much advantage against the most of the decks, so I suggest that nerf to them too. As like:
Shard of Divinity | Shard of Divinity:
In mono-
12 SoDiv gives +288 max. HP and can be 420-488 depending on the original HP. With other healings and 2 Miracles it's nearly 1200-1500 HP at all (Not counting that the 2 Miracles is affected by the Dexterity to). Both of them is spell, so if you can't lock the AI hand for 2-3 turn with Silence, there not really a chance to stand against this.
Shard of Void | Shard of Void:
Within a price of an effect and the opposing effect is can't be declared easily. SoV does it's things slowly, but in a cruel way. But playing in a 30 card deck with 6 SoV and Dexterity is not really slow. It can stack 4-7 SoV easily and this is -12-21 max. life per turn, so a half negative SoDiv or more per turn. But despite of SoDiv, where you can deal damage, the max. HP reduction compensation is not a common thing. And with 12 of this makes PC useless.
Shard of Focus | Shard of Focus:
That's card is still in the 'nerf this card' thread in a good place. 12 SoFocus destroys up to 36 permanent (actually, you don't have that amount), but makes CC-ing them useless (Okay, every Dexterity makes the card destroy effect useless). For the Holy Cow's sake, the AI can't use SoFocus wisely, but still destroys every pend-pillar or anything.
Shard of Bravery | Shard of Bravery
In Arena, this is the rush-helper and a good deckout card too. Dexterity will draw 2 card, so a 30 card deck against a 30x2 card deck is deckouted in the 'same' time. SoBravery allows the AI to make the draw similar and 12 of it destroys up to 36 card from both deck. Yes, in the most of cases you won't play every pillar card to counter this effect, but this makes you slower too. And if Sanctuary played (the only reliable counter against it) it doesn't really counts if AI have a play lock in it. But if not, I think this restriction is needed.
Shard of Wisdom | Shard of Wisdom, Shard of Readiness | Shard of Readiness and Shard of Patience | Shard of Patience:
This can stay as it is. After the 2-3 on the field it's half as effective, so there's no reason to lock up to 6.
Shard of Freedom | Shard of Freedom:
It should, but I don't feel that must have been done.
Shard of Gratitude | Shard of Gratitude:
I'm against myself, but it can stay as it is. 60 healing per turn is the maximal, which is nearly the same as 2 Empathic Bond, just a bit more stable against PC-s.
I'll find Shard of Seperindity a fun card and Shard of Integrity too.
As seen, I've only suggested the restriction to the shards which does unique (and strong) things or combos.