You not only have to generate those spells, you have to cast those spells. It takes a very long time to complete. And we're talking about a combo finisher deck that starts at minus 1 card due to the quest. Kripp is throwing darts and hoping (or not hoping) one dart sticks.
I doubt the deck, when it works, is even as bad as freeze mage. Hell, if you think about it, is time warp even much better than ice block which requires no activation? Time warp enables a few more win conditions, but nothing as bad as we've seen before and "exodia" mage has like a 1% chance of being good.
Uh, yeah, it's way better. Ice Block still allows your opponent to take a turn in between your setup and finish. During which they can heal up, clear your board, play taunts, etc. Time Warp allows you to set everything up and then immediately enact your combo with no interaction from your opponent.
Personally, I think it's very possible that Time Warp will be viable. If the quest is easy to activate then yeah, it will be OP. Lifecoach likes to say the Hunter Quest is "50/50". Either it sucks and never sees play or it's totally busted and completely breaks the game. There is no in-between. I think he's got the wrong quest though. It's Open the Waygate that could break the game.