It is less RNG that you think. It’s better than just high rolling a storm and makes spell totem less frustrating. Strong enough to kill most boards. And not to late to play in time. It’s a card that is fine and doesn’t push shaman even better. Not every card has to be competetive.
You can decrease it’s RNG through your plays.

They appear as the left card in your starting hand. When you play it it’s like a secret except your opponent is able to read it

Why bad? You don´t play it in a standard warrior deck. Maybe in pirate warrior with reaper or with the new weapon for warrior.

Rarity has nothing to do with a card beeing good. Think of Lorewalker Cho. Rarity is about balance in arena. Tech Cards are often epics. This is just a bad card in arena because it´s so hard to pull off. That´s why it´s an epic.

No, dirty rat doesn´t summon a copy. It´s the actual minion. Same as deathlord (they will change its wording).

What? You´re happy with almost anything getting polymorphed. Totem Golem, Thing From Below, Acolyte, Doomsayer, Councilman, even Flame Imp. Thousands of targets. Entity leaves the opponent with the full minion and the chance to deal with your copy. This seems way better.
Also if you play entity + this, you get a copy of the minion and give them a 1/1. And it´s a potion, warlock and priest can get this.

It won´t effect him. Battlecry triggers first. Think of mirror entity.

You don´t replace huckster, you play both. It makes the burgle theme more consistant.

It guarantees a card 95% of the time. No one will clear this off before your first attack. And your opponent will clear it up. They want to deny card draws.
It pushes this mechanic. With more cards with the same effect it gets better. Now you have 5 minions in a deck with this effect. Its not fun because it´s not new?

Aggro has also taunts. Voidwalker, Argus, Feral Spirit, Basic Totem, Thing From Below. There are lots of taunts used in many decks.

No aggro deck will use this, it´s too expensive. Zoo for example uses voidwalker, argus. Shamans have totems, feral and thing from below. It has many targets, which makes it more consistent.

I think it´s better. This weapon has the purpose to attack and trade with it. Sword of Justice wants to flood the board. And the 1Attack difference is important. Fits the warrior theme perfectly.

Why is everybody saying that? The cards are for different classes. You cannot compare them. Spells for mage are very important because of other cards like Mana Wyrm. Mage probably plays minions with spell damage, warlock doesn´t.
It will be used a lot of times.