Hello. I'll explain how to use a bug with which it is possible to get such high crits.
First of all you have to be a Paladin. Retribution.
You get normal gear and gem STR in EVERYTHING. You buy the STR Darkmooncard.
If you are able to, you buy mark of supremacy. You also buy Bandits Insignia.
Now you set five points in Divine Strength.
From now on just specc down into Retribution untill you reach sheath of light. do NOT specc it yet. Now the exploit comes into play:
You must have a second account. Create a warrior, another Paladin, a Death Knight and a third paladin. Buff yourself Lesser BoM. Log on with one pally, invite him, give yourself GBOM. Log out with him (STAY IN GROUP AFTER LOGGED OUT) and login with the second Pally. Invite, buff BoK or gBOK now with him.
Now log onto the warrior. Invite him and battle shout. Log out, onto the DK, invite him. Cast the Horn.
You are now buffed as hell. If you are sneaky even use STR-Potions (one gives you 70 STR for a few secs) but it gets obvious then.
Now everything goes pretty fast.
You now equip your Darkmooncard in Slot 2 and Bandit's insignia in Slot 1. Cast a few (mostly 3-4) flash of lights untill the card proccs. now change Bandit's Insignia to Mark of Supremacy, use it. After you used the mark, change it back to Bandit's Insignia. Now you should have around 8-11k AP. Specc 3/3 into Sheath of Light fast (!).
You have like 2.5-3.5k Spellpower now which will make your judgement crit for an amount of 8-17k.
I do NOT Recommand you to get more then 2.5k Spellpower since it gets kinda obvious then.
I used this bug for a almost one year now, but since I stopped playing there I thought I should share this with you.
The better your gear is the higher amount your AP is. The higher amount your AP is the higher amount your SP will be. Just don't get too much, it's kinda obvious if you stack it too hard.
I was tired as I wrote this, don't be harsh. PM me if you have questions.
Have fun!
By the way, this also works for Arcanemages and Holypallys. (probably even for moonkins) Same thing but you need much Int. which is harder to get then AP. (100-400 more SP is possible after my tests a few weeks ago)