I'm actually a staunch believer that League's F2P model kills the MOBA genre.
The two main concerns are the fact that you need to use IP to buy Champions/Runes. I'll start with Runes first.
Long story short, if you don't have Runes, you're going to lose the lane compared to someone that has runes. You're legitimately putting yourself at a disadvantage because you don't want to spend IP. Okay, that's your choice, fine. However, every good League player knows that buying anything that isn't a Rank 3 Rune is a complete waste of IP, so you have a choice to make:
- Buy runes suitable for your level, which requires grinding like a motherfucker
- Don't buy runes until Summoner Level 20, which means you're starting with a disadvantage in every game, through no fault of your own skill.
Just like that, you're punished for not spending money, or grinding for IP. This is before your personal skill ever comes into play. (You could say that it requires more skill to overcome these disadvantages, but that also means people require less skill to defeat you. It'd be like you're trying super hard for no reason at all.)
The champions are worse, since each champion needs to be bought. Since most players will only have access to a few champions alongside the Free Rotation, the game needs to be balanced around the fact that players don't have access to every champion, so then every champion ends up being the same. Other than a few trending powerful champions (Which players are also punished for not buying), you could replace any champion for any champion of the same role and the game would go mostly the same.
Obviously, there would be slight differences - A Blitzcrank can secure kills better than a Soraka can, and a Riven is going to have more mobility than a Nasus, and a Heimerdinger can hold mid better than any AP mid - but when you look at every league match in general, it all plays out exactly the same.
Your ADC is going to farm until bot T1 is down, then he'll pick fights while farming lanes in between.
Your support is going to harass the enemy support/carry while keeping the enemy support from harassing his carry. After that, he twiddles his thumbs until a teamfight breaks out.
Your AP Mid is going to farm until he's won lane, then he ganks top/bot or maybe aids with Dragon.
Your Jungler is going to farm until he can gank a lane, then he goes back to farming until it's push time.
Your Top is going to camp top forever until he either loses lane or the team seriously needs him.
There's a really astounding amount of champions that follow the cookie cutter build of:
- Spammable Nuke
- Spammable CC with mediocre effect/duration
- Spammable mobility/sustain spell
Do you remember the jungler fuss a few months back? Every jungler is considered weak because they weren't Lee Sin. Then they nerfed Lee to be like every other jungler. Riot's balance philosophy has been like that for the longest time - Cut down a champion's strengths, and cover up their weaknesses.
TL;DR:
- Runes punish/reward people based on time/money spent, not skill.
- Champions must be bought and this forces all champions to be dreadfully similar.