This question has haunted me for ages, now. Like I stated earlier, I’m not pro, and I wouldn’t even consider myself good at this game, but I also realize being “good” at a game involves understanding the game itself to some degree. Your skill will only get you so far if you’re good at a few champions but don’t understand the significance of objectives (like dragon or baron).
Well, since I have a blog about League and haven’t played much lately, I figure I’d answer this question here. I’m sure there might be someone who will learn just as much as I have.

Note: I have  never attempted to understand what defines a champion’s role until now. I’m learning as I make this blog, so please correct me if you see something wrong.

What are the current roles?
As I currently see it, roles are the lanes you play. Like Top, Mid, Bot/Support, or Jungles. I’ll call these “Lane Roles”. However, there are individual roles that each Champion posses. A few popular examples are Jinx who is a marksman, Diana or Kha’Zix are assassins, or Malphite who is a tank.
Now, what’s bothering me, and leaves me wondering all the time – what makes a champion good for which lane?  Theoretically, I guess, you could be successful using any champ in any lane role.

So I did some google searching to find what was the most helpful for me to understand. I certainly learned a few things – like there are usually two bot because they are closest to dragon and should be the ones to help defend/steal the dragon. That makes so much more sense to me now! I guess that’s the problem that I’ve always had, and many others do – they just play the game, and play the way everybody else was doing it. I mean, when I first started I didn’t know why two people always went bottom! I just knew after a few games, that’s the way it was…and assumed that’s how it was supposed to be.

Here’s some good quotes from this LoL Board:

WHY DOES MY CHAMPION GO TO THIS LANE?
Bottom Lane
The reason the Ranged AD Carry and Support go here is because of dragon. This lane is the closest to dragon and they are the most equipped to protect dragon should the enemy jungler try to take it The support usually puts wards there, as is the supports job (among other things). During the laning phase, the duo lane is best equipped for protecting it because the Ranged AD Carry can essentially come in and snipe dragon for themselves and go back to lane. There needs to be a support with the AD Carry because the ADC has a weak early game, and is also squishy. Supports ensure kills and protection.
Also, in bot lane, it’s good to have a support and an AD Carry because you have to share experience points in bot lane, so you level a little slower than everyone else. There are items you can buy and masteries you can select to offset the experience difference, so both players can keep up with the other team. But if you have two damage dealers at bot instead of one damage dealer and a support, then you must also split the gold, meaning that you’ll be behind in levels AND your build. Supports have items that boost their gold income, while it is not beneficial for many other players to buy it.

Middle Lane
Because mid is the shortest of the lanes, the minions reach mid first and the champion needs to be strong enough to control the lane and get all of the minions. Because the minions get to this lane before any of the others, the pacing of this lane is usually a lot faster. There’s generally more gold flow and mid laners are usually at a higher level. Not only that, but the distance between the turrets is also the shortest. Due to all of these factors, a good mid lane champion is one who is able to effectively clear out minion waves, usually with some sort of AoE, and can quickly retreat to their own turret in case of ganks. As I mentioned in a previous section, they deal large amounts of damage, which is another reason that mid is paced so much quicker. There is more damage being dished out at one time and there will probably be more kills here in the early game. Either here or bot.
If you are going to mid lane, you also need to have good map awareness and map control. The jungler does a lot of ganking, but the mid laner usually does it too. Because of the fast pace, they are able to dish out a lot of damage and the usually end up pushing minions to the enemy tower. It’s not always wise to go attack tower because you are susceptible to ganks from both sides. So instead, once the tower is pushed, a mid laner will roam. Depending on the situation, they will go top or bot. By the time they reach the destination, their abilities will be off cooldown. They can go in, gank with combos and hopefully get a kill. By the time they go back to mid, the minion waves are usually back in the middle and their cooldowns are usually off as well.

Top Lane
Beefier champions go top because they are having to hold this lane by themselves. Yes, Mid is all alone too, but they are more likely to get ganks from their jungler due to their convenient location. If you’re going top, you need to be able to survive and trade blows with your opponent because you are going to be there for a while. This lane is also the closest to baron and the tanks are the ones who are able to best fend off enemy teams trying to kill it until allies can arrive to steal baron.

 

I seriously recommend you reading the rest of the post. It states  it was revamped for S4, but I think this part explaining the lane roles really hits the nail on the head. It helped me, I  have no doubt it would help you.

I honestly didn’t find much for Jungler. For me, it’s whatever champions I have that an ability related to monsters. The first one that comes to mind is Mordekaiser with his passive being snagging the dragon ghost. I also find that any champs that are able to play jungle are also able to play other lanes (they’d have to, right?) like Rammus – an excellent jungler, and really great at top lane too. I haven’t had too many problems trying him as ADC either. However, this is all in ELO. So take that with a grain of salt.

 

Well…Did I actually answer my original question? Maybe. I think it really depends on your understanding of the game, and the role that each lane typically has. It’s OK to break the meta sometimes and explore your champ’s options.

Since my goal here is to play all the champs I haven’t yet, I will one day have played them all. I suppose next I would play each champ in different lane roles. In alphabetical order. from to top to bottom. Ha. That will take a while.

 

Anyways, I hope you learned something. Thanks again for reading and League On! Cheers.