I've been playing League Of Legends since about Season 2- around 2/3 years ago approximately. Would I recommend the game? No. You'll become addicted. I don't care how much willpower you may think you have, you will inevitably dedicate numerous hours into the game.
As for academics however, there is an assumed correlation. As you input a copious amount of hours into something that's not beneficial towards your education, your optimal intellectual level won't be reached. This isn't necessarily true.
1)Working hours on end isn't very efficient due to fatigue.
2)Your education is heavily dependant upon your motivation.
I'll use myself as an exemplar.
I love League Of Legends, but I love my education more. I will want to play League Of Legends, but I will ensure that I get the grades that I feel comfortable with before hand. I can put League Of Legends aside because I have the motivation to focus on my studies. Also, I tend to use League of Legends as a stress removal device, but that's just me. :P
Ultimately, what I'm trying to say is that there's no reason to neglect these sort of games, as long as you can sort out your priorities. If you can't, don't play the games. Addiction is very odious and if you can avoid it, please do.
Side Note: Good luck on your studies; please wish me a good outcome for my Mocks beginning on the Tuesday coming up, through to Friday. I appreciate it! ^^