In my opinion, nerfing is the uncreative and lazy way to try and fix a stale meta. All it really does is cause a power vaccuum where the next powerful deck steps up to its place, to which will remain because there is no second wave of nerfs. Don't get me wrong, there are good times to nerf since it's why pencils have erasers, and all that (e.g. Cor-Creeper). However, it would be far more effective instead to give the 3rd tier decks a nudge to try and compete. Every expansion brings about more of Team 5's half-baked ideas that intrigue and gain fanfare but ultimately wind up being footnotes because they just can't compete with the broken few that pass through at the same time.
Is it really such a request to ask for these to be buffed? This expansion was especially fun during the first few weeks. All kinds of weird stuff were running around and even a lot of unplayable concepts from the lackluster last three sets saw light. Is it not fun to have a true diversity in the game? Playing and playing against the same 3-8 decks is so tedious that the game just becomes work. As far as I can tell, Blizzard is not capable of projecting the meta, to this I don't blame them. Where I can blame them is for not adjusting it accordingly short of the expected nerf hammer which reads, "this tier one deck drops in power/ the tier 2 deck it counters goes to tier one." a.k.a. nothing very new much emerges.
I get the concept and i'm not opposed to buffing some cards that are unplayable bad, but nerfs are better for balancing the game. there is an ideal balance they want, and there are more cards that exceed that level than there are on the level. It would be easier to just bring those cards down than move random other cards up.
I don't need to. You just take the statistic of a card's playrate/winrate and adjust it accordingly. Usually they just need a stat boost or a drop in mana. Fel Lord Betrug the least successful legendary of RoS could be a 5/9* minion for example. Nozwhisker could be interesting if the mana cost and stats were a little lower.
Sure some cards that should make an archetype function can be buffed, but there are way too many weak cards to buff more than we nerf. Nerfing a few problematic cards is easy, blizzard is just dogshit at it.
If Blizzard would do one major buff patch to bring up the power level of a whole swath of cards that are severely under-utilized (or never used at all), the power level of the whole game would tick up a notch, many more options would be available, and everything would feel more powerful (and therefore more fun), even when you lose.
That being said, Blizzard will never do it. The only "buff" I've ever seen from them was adding more beasts to the pool of Deathstalker Rexxar
When you buff a card, you have to consider all the interactions it has with other cards. You have to do that for the current cards and future cards. Buffing can create the same exact problem that we face when they unknowingly print a card that is too strong.
Nerfing drops the power level and creates less of a problem. Now buffing could possibly work, but its hardly a simple thing.
Buffing is not better than nerfing for changing the meta.
Let's say we buff... Betrayal. Nobody plays Betrayal right now, right? So what happens? People test out Betrayal in their Rogue decks, and either it makes the cut, or it doesn't. That's pretty boring.
Let's buff a different card, one for a class not in the meta much right now. I haven't seen a lot of Priest, what happens if we give them a buff? Well, now people try out Priest for a bit, and either it changes the meta up, or it still isn't strong enough to be Tier 1-2. Not much change, and either way the average powerlevel of the game has increased, which isn't good.
Now what happens when we nerf a card? Let's say we nerf Waggle Pick, since that seems to be one of Rogue's strong cards right now. Now we have a lot more interesting developments. First, we need to see how much of a hit this is to Rogue. If Waggle Pick is hit hard enough, what card do you replace it with? Do you need to change up your strategy completely? Then we need to see what Tier 2-3 decks can take advantage of this new drop in Rogue's powerlevel - maybe Zoolock becomes much better now? Or Midrange Hunter? What about Warrior decks, how does this affect them?
In general, nerfing cards creates far more opportunities for change than buffing cards does. Buffing a card means you try out that card; nerfing a card means trying out a bunch of cards to see if they're better than it now.