Hearthpwn

this card is soooo hyped everyone is playing it... 

People seem to ignore the fact that the cards are put in after the mulligan. This means your starting hand should be solid even with Malchezaar, or as solid as it would be if you weren't playing it. Sure sometime you can get screwed and draw your 5 legendaries in your first 5 turns, but it's not something that will happen often. I mean you can already draw your 5 biggest cards in the turn 1-2-3-4-5, but the odds are like 1 in a million, with Malchezaar it's one in a hundred thousands? 

Having one or two of these legendaries slip in your first 5 draws shouldn't be THAT dramatic, given that you have 4-5 cards in hand when it starts and draw 5 more in the first 5 turns ( at least 5 more ) so that's 9-10 cards total minimum. 

Now look at it the other way. Oh sure, some legendaries are bad. Bad as in not mana efficient. But mana efficiency isn't the only thing that matters. Threats is another. 

Boogeymonster is horrible, 8 mana 6-7 plus a small bonus text... no one would want to put that card in their decks. But sometime yo don't spend your entire mana pool in a turn, espeically late game.  If you top deck a enchanted raven turn 12 and that's the only playable card you got, your entire mana pool will be spent to drop a 2-2 and hero power and waste 7 mana.
You could instead drop a 6-7 and hero power. Becuase you don't only darw big cards early, sometime you draw small cards late. And if you waste 6-7 mana, any cards that use these mana is basically "free". IT's just like having a 1 mana 6-7. Even if it's a terrible card, you'd take it in that situation. 

If the legendaries were put in anywhere in your deck (including starting hand) it'd be unplayable and you would have zero reason to use it, you could just put the legendaries in your deck and get the same result. Better even, because you would not use the absolute worst ones. But putting them AFTER your starting hand makes it insanely better. People are always happy to draw cards like ragnaros and tirion and all gromm and all that late game, but they don't fill up their decks with them, why? Because drawing them in your first 4-5 cards can make you lose the game. 
With malchezaar, you have 4-5 cards 'safe' from drawing these legendaries. This makes all the difference in the world, and while you won'T always get a good legendary like tirion, you'll often draw something better than the average of your deck. 

You don't believe me? Take a crap legendary, like I don't know Hogger. When the game hits turn 10 or so, look up the cards you have still on your deck, and compare them to Hogger. Think about which card you'd like to draw between them individually. Hogger or enchanted raven? Hogger or wrath? Hogger or innervate when you  can't really spend 12 mana efficiently? Do your whole list like that. Guaranteed you'll see that even bad legendaries are better than 'average card in your deck' during the late game phase, because your deck is always full of early game stuff. 

I'm ambivalent about this card. The legendary minions you get could be useful, could be trash. The thing is you have no idea, so you can't play around them. Plus padding your deck like that increases the probability of not drawing into a good card for the situation. I think if it revealed to the person playing the card which minions they are receiving it would be a much stronger card. At least then you can try to plan around what is trash and what is not. Otherwise it's too inconsistent for ranked play. Arena is another matter though due to the nature of building your initial deck. If you have a few instances of having nothing but trash cards as your 3-pick, then at least you have a chance to draw a decent legendary instead of one of those picks once play starts. Unless you were screwed and got trash all the way around, but I digress. As for those talking about this being like the discovery mechanic, that's a false equivalency since discovery puts the card directly in your hand, not shuffled into your deck. Big difference. A closer example is Forgotten Torch, since the generated card it's placed randomly into your deck. But at least it's a 3 drop that does 6 damage wherever you'd like (nontargetable minions notwithstanding).

The first time I played this card, I drew 3 of the 5 random Legendaries on turns 2, 3 and 4... Fucked me in the long run

This card is absolutely awful, unplayable. What on Earth are you guys who voted it "meta-defining" thinking? It's barely even playable in Arena. It literally just makes your deck worse by making it more than 30 cards. If you want legendaries, put the legendaries you want in your deck.

Increasing your deck size is a BAD THING. There's a reason every single Magic deck is exactly 60 cards (the minimum) despite being allowed to have as many as you want.

Discover isn't even slightly analogous because it produces card advantage (it's essentially pseudo-draw).

this is actually one of the best cards in arena 

This card is also extreme useful in the spell heavy decks that aren't playing necessarily for the curve but to control and hit their win condition.  those legendary's they get from him are drops along the curve they wouldn't normally have and give them presence they normally wouldn't have.  He's also priced very well for his stats just by himself.

I thought mill decks out there would have a difficult time to burn out their decks but i was wrong. More cards to burn, that's all, beat 4 control warriors with Prince Malchezaar by playing Mill Rogue today.

A misdraw (drawing a legendary you don't need, instead of a card you need) could lead you to defeat, and 5/35 is not a small chance.

It can be good in control/fatigue decks, that can also afford to add more draw power in order to neutralise Malchezaar's randomness.

Pretty bad in any faster setup.

Ok, I guess Malchezaar is kind of good then... :D

Sad mill rogue, perhaps?

can he also adds another class legendaries into my deck? for example i play control warrior so can he add tirion and malorne into my deck?

that's really sucks, why they didnt allow that?

if they allow random legendaries they should also include the class legendaries as well

No thanks, I'd rather not have warriors with Tirion and mages with Grom. 

Because it would make zero sense gameplay-wise and flavour-wise.

Well, actually, he can put random class legendaries from the class that you playing, but in 50+ games I see it once ( and it was Eadric the Pure :(  ).

You lost because you removed Harrison. simple. 

OK, I thought this card was trash tier, but then played against it in a control warrior and now I'm really wondering.

Crucially, it adds the 5 random cards to your deck AFTER the starting hands are determined, so all this talk about ruining your early game is significantly less severe than I was anticipating.

I think he's potentially an awesome, moderate variance control v control tool.  He means you can shamelessly draw with acolyte/slam without worrying about fatigue.  He is, of course, a bit of a liability against aggro, where (a) he's diluted your draws (you probably draw one dead card in the first few turns where you need to get control), making your stating hand very important and (b) a vanilla 5/6 is not exactly setting the world alight.