SC2 is not boring. It's pretty challenging and fun to play, even at lower levels of skillset. So that's an incorrect statement. Subjective oinions.. everywherreee
HS is casual? Okay, why aren't you the top #1 player in the world then, since it's so easy to be good at ? Sure, it's no MTG, but it doesn't need to be. HS is VERY successful, fun, fast and enganging. It's complex and innovative. A smash hit. You might not like the game, but saying is casual is also flat out wrong.
Heroes of the storm, while at first sight, might appear more "simple" or "casual" than the other MOBAS, brings something unique to the game. It's vastly differenws.t from othe others, and it shows. Fun, fast, engaging, simple to get into, but still complex enough for staying power.
But yeah, subjective opinions. But given how successful all of the above mentioned games are, it's clear that that they are good and fun games for a large majority of genre specific gamers.
You can deny that if you want, doesn't make it any less true.