reakoMenachemOnce you get to a certain point, no competitive title is more difficult than any other.
overwatch
hearthstone
compared to
cs
quake
they require different skillsets, but by definition theyre equal in straight up difficulty. You're not playing against the game, you're playing other players, and compared to the other people playing you're not any more likely to get better at one game faster than another. In Overwatch there's an argument to be made about a lower mechanical skill ceiling, but generally the same people have been playing at the highest level for most of the game's lifespan. There aren't really a lot of newbies that I know of that start playing the game and then can be considered one of the best in a short timeframe.
As for hearthstone, isn't it a trading card game and therefore requires luck of the draw? definitely not a great example of a competitive game.