I am generally confused because even if you tried to do something crazy with this, it requires the 'perfect' draw.
In Wild, I see lots of play with this, but in Standard, not so much. Standard review below.
Paladin has no capacity to throw minions back into their deck, other than Banker.
So let's pretend none of that matters. What is the best scenario? I always like to talk about the floor and the ceiling. What is the ceiling on this card? Meaning, what is the most absurd thing you can do?
Well, you get 2 Bluegill, 2 Murloc Warleaders, 2 Grimscale Oracles. How much damage is that going Face?
16 damage going face the turn you play this for 8 mana. IF and only if you never draw your Murlocs during the game. if you do, you will then have to Banker them back into your deck before you play this card.
After you play this once though....uh, no more Murlocs in your deck. Or you got really lucky with the above.
So the BEST scenario, is you play 1 copy of this and hope for some perfect draws.
Otherwise getting a full board of Murlocs on turn 8 will get removed by most classes. So, in a standard aggro Murloc deck, this is terrible.
Only potential is to fill your deck with Murlocs but only Bluegill x2 and Warleader x2 and then thin your deck out in a combo style OTK deck. This gives you damage in order to not have to do 30 damage all in one go.
I think this is Christmas land thinking. The floor on this is absolutely terrible. You draw all your Murlocs and this card does nothing.
If so, then this might be decent. Otherwise, most of my murlocs I like to play have a Battlecry and therefore, I lose this effect. The ones I use for the Wild Anyfin can Happen would ONLY play this so you can have 3 and 4 copies of Anyfin. The issue is that you CAN'T draw your murlocs if that is the case. But the deck wants to draw through the whole deck so you can get all of your Murlocs killed AND hit your ANYFIN on 10.
I dunno, I am trying to see if I build the deck differently, but without mid range Deathrattle Murlocs, I would never want to play this.
Treat this like the 8 mana Druid spell that gives you 5 Treants. What if that Druid Spell didn't have Twinspell. I think it would never be played then. This is like the 8 mana Druid spell, but NO Twinspell AND requires you to build your deck with specific minions.
I think it IS powerful, but only because of very narrow and specific scenarios. You are cheating out mana afterall. But is 8 mana too late?