well, i spent months away from league playing HotS
and i have a completely new perspective on league.
i used to hate league because it was full of ragers/quitters/people who just didn't care if they won. and sure. it is. just like heroes is.
but here's the key difference.
_In league, there are noticeable differences between divisions/tiers. _ say you play in bronze 5. the players there are real bad. but say you climb up to silver, the players get substantially better, make better decisions(sometimes), and have a general knowledge of the games. you can generally assume someone in high platinum has a high MMR
now, in heroes they go by a rank system AND an mmr system. the rank system, i.e the whole reason you play competitive is a complete joke.
a rank 1 in heroes, the mmr range goes anywhere from 2000(silver mmr) to 4000(master mmr). these players are considered the top 2% of players in the game based on their rank. the issue, is that the game's matchmaking is completely luck based, and based on queue times. there are players who are in the top 70% players with 3k mmr who are at rank 35 only because they were'nt lucky enough to go on a big win-streak for these guys.
it's a completely garbage system, full of easily exploitable loopholes(like creating a smurf, stomping low levels, and doing mildly well in your placements while duo'd with a high rank friend. so what you get, is a bunch of people with less than 300 games sitting at rank 1 while having an average MMR at best, while the people who have been playing since beta with 1000+ and a good mmr(2500+) sitting at the lowest ranks in the game because mmr has NOTHING to do with your rank. it's also damn near impossible to just carry your team no matter how good you are. so you get extremely high ranked people matched together, and there's massive glaring skill difference between them even though they may share the same rank.
in league if a diamond is playing with bronzes, odds are he's going to carry them regardless of how bad they are.
in heroes, your whole game is dependent on the weakest link on your team. teamfighting is extremely prevalent due to global objectives, and since everyone shares levels, if one guy isn't doing his job the whole team suffers because of it
tl;dr blizzard is really shitty at pvp and heroes is a massive disappointment because of that.