I've half quit too, used to play 5 games a day or so but I've completely lost my incentive to play for a multitude of reasons. All of which can be traced back to Riot wanting LoL to be better to watch than play.
I have a few certain playstyles that Riot keeps gutting:
1 - Tanks
I used to love tanks and other more selfless, CCful roles like initiators, meat shields or just general team utility tanks. Best example would be Shen, who currently gets gutted by 90% of all top laners and is somewhat forced into the support role which I guess he does okay. In general everything melts tanks now and tanks just aren't tanky enough with true damage or max HP damage or executes all over the place. This is mainly due to Riot wanting to buff all damage to have more 'play making' whereas tanks can potentially be generally boring to watch play as an audience.
2 - Defensive/Passive Supports
I'm the guy who likes to have a less 'clown fiesta' game especially when it comes to early game, so back in the day I really preferred Nami, Soraka, Janna, classic supports who more or less counters initiations from classic initiation supports like Leona, Thresh or Alistar, but nowadays mobility and burst is everywhere, as well as shields being nerfed, on one hand, everyone's mobility makes your very limited peel useless whereas their burst goes right through shields, healing and buffs. Even at the best of times, supports can only shield/heal around 60% of the average burst damage if they get lucky. Otherwise these kinds of supports are now either played super aggressively (currently trending "Battle Mage Soraka" build) or are just too outclassed by everything that's happening around them.
3 - Medium ranged control mages
Due to relatively the same reasons as above, medium ranged control mages are generally outclassed right and left, specifically Orianna. Everything she has in her arsenal can be countered by whats popular right now. Her Q is easily dodge-able due to being a medium ranged skillshot with so much mobility right now, and same goes for her W. Her E doesn't shield for that much and has a decent travel time, burst damage dealers can basically ignore this with the amount of damage going on right now and her R is only really a temporary fix for burst/mobility. Her biggest strength is probably wombo combos but wombo combos just don't happen anymore with assassins and carries bursting down people right and left before you even have time to group.
4 - General mobility
Well hey, mobility is fun to watch for the audience right? It used to be that 'anyone who has mobility has an extra form of offense and defense'. Now, it's 'anyone who doesn't have mobility will absolutely get outclassed by those who do'. The endless amount of mobility allows anyone to dive turrets without a sweat. There's no counterplay to that even if the 'safety' of your turret. Why is this? Mobility. And burst damage I guess.
4.5 - Turrets
Yeah, they're useless now.
5 - Burst Damage
Why did LB originally get a rework? To increase the delay times between her burst for room for counterplay. Why did Fizz's W get a change? To increase the delay times between his burst for room for counterplay. Why did Yi get a cooldown refresh delay from kills during his ultimate? To increase the delay times between his burst for room for counterplay.
What's Riot doing right now? Getting rid of that delay in other champions. This point has been said enough by others. This game lost it's teamplay strategy and is now focused on the individual strengths of each champion and their capabilities to 100 to 0 someone. That way, no one needs map awareness, just do your best to burst someone when you find them.
6 - The general jist of all this
I remember reading somewhere, someone pointed something out that made a whole lot of sense, and unfortunately it's not something Riot's going to address since they're a business. On one hand, more mobility and more burst damage is more appealing to watch, especially in the pro scene, a large playerbase of LoL are Chinese teenagers who play in internet cafes. As a result, Riot needs to make LoL into a super fast game which ends before 20 minutes to satisfy those Chinese internet cafe gamers as well as something flashy to make the casual watching audience intrigued by the intense action. LoL went from a strategic game to an intense game of cat and mouse, where the people who catch out the opponents (which is easier and easier to do) the more they'll win.
Conclusion
Is this unhealthy for the game? I guess for us but definitely not for those Chinese (or Asian in general) internet cafe gamers, they're having the time of their lives, especially with the average Chinese teenager being rather egotistical about gaming (accuse me of being racist or not but this is too true), Riot needs to satisfy that playerbase, especially since Riot is owned by TenCent, a Chinese corporation.
So yeah, the game I fell in love with back in 2012 just isn't the same anymore. I've tried to put up with its bs from time to time and much of it was absolutely manageable, but this is going too far out of what I consider fun and entertaining and its gameplay is becoming more and more toxic by the patch. As bad as this makes me sound, I truly can't help but feel like I can't wait to see this game end. I no longer want LoL to improve, I just want it to die. I dunno why, I never say this but I can't deny myself feeling it.
[sg-soraka]
PS: I should probably also mention that other things in my life have come into play so I have other things I want to dedicate my time to other than LoL so I guess that's another big factor
of course. And than you have mage assassins like 
who pretty much do that too without even building an insane ap item.
