I have lots of thoughts and advice below, but to summarize:
Most of winning top is counter-picking appropriately. Counter picking with an AD carry is easy:
- If they pick their top first there is almost always a ranged AD carry that counters their pick.
- If you have to pick first, you can bait your opponents into countering the wrong lane.
To elaborate on the second bullet: because of the meta, you picking an AD carry first will lead your opponent to counter your AD carry for the bottom lane. If they then pick their top, your team has a chance to counter their counter-pick with your actual bottom lane AD carry, which will give your team an advantage in the bottom lane. Assuming you can hold top with your pick, your team starts the game with a two-lane advantage. Of course there are ways for your opponents to keep this from happening, but you can imagine situations where it will work and it won't. Point is it has a high probability of working until people catch on. Ranged carries I recommend: Vayne, Jayce. Others you will have to figure out for yourself.
In terms of changing team dynamics:
- If you don't build a tanky AD carry, then your team will lack the typical top bruiser who starts team fights or shuts down squishies. You will have to have someone else on your team engage, but you still serve the role of shutting down their squishies. Be extra careful when engaging!
- Farming should be easier because you have range, just make sure you can trade damage so their top will think twice about fighting you.
- Avoiding ganks is easy if you have a dash or a way to push champions off of you, especially since you will be closer to your tower of safety with the added farming range.
My Messy and Poorly Organized Thoughts
Playing an AD carry top is viable, as is playing any champion top. The trick is knowing how to win top, assuming they are playing an AD bruiser as is typical of top. To win top, you basically have to do a few things:
- Avoid getting ganked.
- Trade damage really well.
Farming is guaranteed if you can trade damage, because your opponent will have a hard time preventing you from farming when you can deal lots of damage to them. Also, ranged carries have the extra advantage of having a little distance between them and the minions, whereas melee champions have no choice but to get in close to minions in order to farm.
So the rest of winning is in avoiding ganks and trading damage. The key to both really relies on two things:
- You have a way to get out of a fight.
- Your opponent doesn't have a way to get into a fight.
The reason for this is that ranged carries usually can't take a lot of damage, so if 1. or 2. doesn't hold then the second you let a bruiser get in range of you, unless you have a lead, you will probably die. Also, if 1. doesn't hold you are very vulnerable to ganks, which are extremely easy to pull of against most squishy ranged carries if they aren't hanging back.
To explain those two things better I will give three situations for top lane champions:
Good situation: You - Vayne, Them - Singed.
- Vayne has Tumble and Final Hour which makes her invisible while tumbling, meaning she can disappear from fights when she needs to. Also, Condemn can keep champions away from you.
- Singed has Mega Adhesive, but it can't reliably get him close to Vayne because she can simply Condemn him away. The cooldowns on these abilities are similar enough that Vayne is guaranteed safety.
So, Vayne will be able to pound on Singed as much as she pleases with Singed having no hope of retaliation. Sounds good to me.
Even situation: You - Vayne, Them - Irelia.
- Again, same as above. Plenty of ways for you to get out.
- Irelia has Blade Surge, unfortunately meaning she can get in your face easily. Unless you have superhuman Condemn reactions, she will also likely stun you with Equilibrium Strike immediately after jumping on you.
So, although you can get away, Irelia will trade damage with you. Winning from here on is pretty situational, and you will have to get ahead to guarantee any sort of laning presence top lane against Irelia.
Bad situation: You - Sivir, Them - Well, lots of people
- Spell Shield - awesome way to shut down any targeted spells that may cc you. Unfortunately, she has to auto attack in order to get enough speed to run away - no dashes, no way to push champions off of you.
- Nocturne can speed to you with Duskbringer and fear with Unspeakable Horror if you make the mistake of blowing your spell shield too early. Xin Zhao can gap close like a monster, slowing and then getting a chance to stun. You can either choose to shield the stun or the slow, not a decision you want to be stuck with. Etc. etc...
Basically, any bruisers that can get close to Sivir will eat her alive, and most bruisers can close gaps. You will really have a hard time exchanging blows top, although with plenty of mana and care you may be able to at least passively farm. Not a great pick.
So, as you can see picking a ranged carry top is definitely workable. The trick then is really in counter-picking appropriately, so you know who you are up against before making your choice.
Basically, if you play Normal Draft Pick or Ranked games, you get an opportunity to pick your champion after your opponent does, meaning you can pick a champion that counters your opponents' picks. Because the meta game is well-established in League of Legends, it can be pretty easy to determine which of your opponents champions will go in top lane - i.e. for the current meta it's usually an AD melee bruiser, with a few exceptions (ala Vlad). For help in determining which champions will be going top lane check out Champion Select, which as a tool can help you learn which champions usually go top, and how to counter them.
Unfortunately, that site only really covers usual lane combinations - it won't tell you which AD range carries counter bruisers. However, if you go my examples above you should be able to figure out if you will be able to lane against any champion they pick.
The newest champion has an amazing amount of versatility, making him a great top pick. He can go ranged like any other carry, or become a mean melee. He has some defensive moves and plenty of ways to farm well and trade damage. I haven't played him so I can't personally vouch for an instant-win, but I recommend trying him out. Will post more info when I have more time to think about him.