Restarting the game returns this from exile, and even if it didn't, players searching hidden zones can legally fail to find cards there with specific search criteria. Wording suggestion:
"Reveal your hand and library. Exile all cards you own named ~ from all zones.
Restart the game, leaving in exile all cards named ~."
I wouldn't even worry about shuffling, since that's part of restarting.
Restarting the game returns this from exile, and even if it didn't, players searching hidden zones can legally fail to find cards there with specific search criteria. Wording suggestion:
"Reveal your hand and library. Exile all cards you own named ~ from all zones.
Restart the game, leaving in exile all cards named ~."
I wouldn't even worry about shuffling, since that's part of restarting.
Now I fear Purify is not exciting enough to be a mythic. (Back to Nature was a 2-mana uncommon; Tranquility was common.)