Hearthstone is doing something really neat with its draft format called Arena. In Arena right now the player is shown a set of 3 cards, chooses 1, and then does that 29 more times to make a 30 card deck. The sets of 3 are all of the same rarity - common, rare, epic, and legendary. That sameness of rarity does basically nothing though because rarity in Hearthstone has little effect on card quality or type.
When choosing cards you have to account for two things - first, how good is the card in a vacuum, and second, how good is the card in the deck that you have. Bonemare is really powerful, but since it costs 8 mana you simply can't load up with 6 of them because you will lack early plays.
Hearthstone just announced an intriguing change to the system. Instead of grouping card picks by rarity they are grouping them by power level. Blizzard is going to figure out how good cards are in Arena and then offer 3 cards that are all similarly powerful. You will still have to figure out how well the card matches your deck, but you will not have to worry about raw power.
Right at the outset this will clearly reduce the skill in deckbuilding substantially. You will still have to manage your mana curve and make sure your deck has the cards it needs but people are not going to pass up high powered cards by accident anymore. In particular someone who only dabbles in Arena will have a massive advantage because they are likely to be aware that they need a good curve and should have some specific bases covered like AOE, big removal, etc but they will often not be sure which specific cards are of the most use in Arena. The system will now take care of that for them.
I would expect to see win rates for the top players to go down when this system arrives. Obviously poor players can still find lots of ways to lose games but one axis of incompetence will be removed and that will matter a great deal.
That isn't a criticism. Just a fact. I don't mind the system being changed this way, and I expect the rubes will like it a lot.
A couple of obvious notes need to be made. Clearly in a system where card quality varies a lot from card to card an average pick will be much better than an average card. If all cards are rated from 1-100 then your average pick will be ~70 or something like that because you get the best of 3. However, in the new system cards will all be the same tier so Blizzard will need to substantially reduce the occurrence rate of really trash tier cards or we will regularly be picking between cards that are nearly worthless. They say they are going to do this but no numbers have been supplied so we can't yet know if overall deck quality is going up or down.
Blizzard also hasn't said if they are going to control for overall deck quality. Is it going to be possible to be offered 30 sets of absolutely awesome cards, or 30 sets of trash? If not, how tight is the system going to be? They could easily make it so that every player gets offered a specific number of picks in each tier of cards to make sure that each deck has similar potential, like so if all cards are ranked 1 to 100:
90+ 2 picks
80+ 4 picks
70+ 5 picks
60+ 6 picks
50+ 5 picks
40+ 3 picks
30+ 2 picks
20+ 1 pick
10+ 1 pick
0+ 1 pick
This arrangement gives you a deck that is similarly powerful to current ones, but makes sure that every deck gets a few bombs and a few duds. There will still be substantial variance in deck effectiveness because of mana curves and specific utility but it will cut the variance in the system hugely from the current situation.
One other interesting question is how they will handle the dramatic differences in class power. If a warrior has few powerful cards then potentially they just get bad decks - this is the current system. However, in the system I outlined above it would simply give warriors lots of neutral bombs to make up for the lack of powerful class cards they have. I don't advocate for all classes to be the same by any means, but I do like the idea of closing the gap that currently exists between the power level of classes in Arena.
Hopefully they will announce more details on this shortly so we can see where they are headed. In any case I think these are fine changes, but without more details I can't be sure if I love the new direction or merely tolerate it.