I think the wording 'stupid idea' is a bit harsh, but I don't think it would work out that well sadly. It feels like something new players might end up using and spending on without a full knowledge of the meta due to their inexperience in the game. It sounds too much like a way to sink money for a player that won't fully grasp the game yet, and then they have gained nothing when they recognize the deck they made wasn't fully up to snuff. That said it is only my opinion, and I appreciate the thought you've up into it, even if I don't feel its the best solution.
It reminds me of MtG Online's "Planeswalker packs". I bought a heap of cards thinking I could dive right in. Nope. They can only be used to play other people using the same packs. Waste of cash.
Your idea is somewhat better. But then, new user's will either build a terrible deck (with what they initial think are good cards) and have to pay, again, to fix it. Or they will build net decks.
I think a better idea would be for a free to use "deck of the week/month". Even if it was only for x ranked games. Maybe last month's number 1 deck in standard? This would massively even the playing field, and reward players who can fight the meta and build counters to the best deck.
I don't think this will help much. Or let's say, this is not helping new players or the game as a whole.
New players don't even know the cards, nor how they or the respective decks work. I'm sure a lot of new players spend their first week in Hearthstone on YouTube and Twitch to learn the game and then think "woah, this Odd Paladin thing is the best deck ever" and want to play it instantly. But giving them a pay2play option to get a foot in the meta without really obtaining any cards is just treating the symptoms, not the disease.
Ideally, new players should be able to learn the game on their own, build their collection, get cards piece by piece, and just have fun playing the game, without getting demotivated by snail pace progress and getting crushed by veterans on rank 25. This is what should be worked on.
While it might sound like a good idea to let players just build a netdeck for a low price to start out, from a game design point of view, it's better to give players a sense of progress in their playing experience, and motivate them to work towards self-defined goals, instead of throwing everything at them right from the start.
When you start of with Murloc Raider and Bloodfen Raptor, it feels good to pull a Worgen Infiltrator and a Faerie Dragon from a pack, and notice how your deck is getting better and more interesting, even if it's just baby steps from obtaining cards with minor abilities. Or pulling class cards, that feel more special than neutrals. And from initial, small successes, players are supposed to get more familiar with the game, and get more interested, and THEN start looking what cool things you can do, and what decks are the strongest around. And from there, they can either choose to spend money or try to get there by grinding gold, collecting dust and craft the cards they want to use to eventually get that deck they are interested in. And the latter should be an attractive option as well, not just for masochists with way too much time, because otherwise, you lose a lot of players at that point where they might not know already, how much they want to commit.
This is the new player experience, that Blizzard should try to maintain, or rather recreate.
Your idea is just trying to ease players into a competitive scene that should only be a small part of the entire game and definitely not the focus of any new player. Unfortunately, by now, almost the entire game is as cut-throat as LoL, and even Arena is mostly populated by people who only and exclusively play Arena with third party drafting tools.
I don't mean to attack you, but your idea doesn't change anything about the fact, that the game is in a terrible state for actual new players: You better know how to play the game right from the start, and you better have an optimized deck before you play your first game... that is the real problem.
This approach might suit some people who want to try out new decks without crafting them. But it won't make the game more friendly towards new players.
Yeah, those three options are not very appealing. I definitely did not get any positive reaction to this idea... (none of you were harsh, I put it out there for opinions). There must be a solution. I love this game and want to see it continue to grow. I have just been reading too many posts about the horrible state for new players. Once you have a collection, I find the game is very fair for free to play or to buy in a little...
Maybe Blizzard could unlock a different class each month for experimentation.