If the target creature dies but that card leaves the graveyard before the persist ability resolves, it won't be returned to the battlefield
Also, once again, in 1v1 gameplay, you yourself will be one of the 2 players, meaning your equipment, controlled and owned by you, will fall off the creature because it can't be targeted or equipped by your stuff as soon as it has protection from you, making it quite the useless sword
This is certainly a trend we've seen as of late and it's more than likely a lot to do with metagame/sideboard choices and also hedging in hate versus Uro based decks
*Shakes Magic 8-Ball* My sources say no
Bad Mechanic Hosers (Nine-Ringed Bo, Tombfire, Root Cage, Trapfinder's Trick, etc) There are a number of mechanics Wizards of the Coast were clearly worried about when they printed them
Goblin Ringleader is legal in Pioneer, but similar to Modern I dont know if its playable here