I mostly play Arena in Hearthstone these days. Drafting decks is tremendous fun and I really feel like I am getting better at figuring out weightings for my picks. I used to end up with decks that simply didn't have enough late game or were too slow and I am balancing that much better, finding a good mix of costs and draw. One thing I am finding though is that Arena feels more random than it used to, and I think that trend is simply going to continue over time.
I watched a video by Kripparrian where he talked about his new strategy for avoiding board clears by opponents, which is to simply ignore board clears and go for it. Overextend! Spew out dudes! Of course sometimes they do have the board clear and you get blown out, but most of the time they don't. This is a big change from previous eras, but it all makes sense. Blizzard has not been publishing many new board clears, or even new removal spells. The ones that do make it are situational or downright bad most of the time. The classic board clears only appear in a single set, and as the card pool grows they make up a smaller and smaller fraction of decks. As time goes by Arena is going to contain a greater percentage of minions and weird cards and a lower percentage of premium removal and board clears.
This has two major effects. Firstly it makes Arena much more tempo driven. You can't rely on board clears to reset the game because you probably don't have any clears. That means you need a bigger focus on cheap minions and early game board control. Missing a 1 drop is going to become a bigger deal because that 1 drop won't just get cleared out at some point. Losing control of the board because you missed a 2 drop will be much harder to reverse. There is obviously still skill involved, but against any moderately skilled opponent who actually gets a 1,2,3,4 drop sequence it will be extremely difficult to come back if your draw is awkward or top heavy. The emphasis on early game will only get bigger and the quality of the opening draw will become more important as time goes by. This also means that board clears are even better because people won't be playing around them and so they will get maximum value a lot more often.
There is also a general reduction in the ability of a good player to anticipate what the opponent will do. Baiting out hard removal with a big minion in order to protect an even better minion becomes foolish when the opponent probably doesn't even have a hard removal spell. Playing around a board clear is pointless when there are hardly any around. Even just thinking about which 4 drop the opponent will use can be silly when the pool of 4 drops is ever increasing - at some point you just accept that you know nothing about what will happen next. Of course there is still skill in playing the board, and you can still think about generalities like "what will I do against a big taunt?" without knowing which exact big taunt it will be, but the amount of skill that can be applied definitely fades.
The fact that websites like HearthArena offer really good advice on picks and are updated very quickly and the fact that predictability in games is going down means that win rates are almost certain to flatten over time. This is a slow process, obviously, but I suspect we will see a situation where the best players see their win rates drift downwards while the medium players, especially those that use outside assistance for drafting, see their win rates rise.
This is not to say the sky is falling. After all, there is always some luck and some skill, and now the balance is shifting slightly in favour of luck. I am not claiming that Hearthstone is currently at the perfect spot, so a shift is just a shift, not necessarily bad or good. However, I do think that the shift is unavoidable.