This is the second of a series of threads made to discuss the different aspects of a LoL team composition. The first one (tanks) can be found here: http://www.leagueoflegends.com/board...ad.php?t=51281
The goal of this thread is not to teach someone how to play a caster, but rather educate newer players on the general philosophy behind the role of the caster. Hopefully, this will open up more educated discussions and perceptions of what each character's strengths are, why they are brought to the team, and why characters like Annie are considered better than characters like Ryze.
Casters in LoL are pretty varied. Which ones you have on your team will drastically alter the way your team fights. Here are some of the main reasons to bring casters to your team:
1) To mix up the damage types.
A team of all carries would let your opponents just stack armor. Forcing them to mix up their defenses makes it more difficult for your opponent to gear defensively.
2) For their disables and control (CC).
In general, casters have stronger disables than carries. Hard disables are extremely powerful in LoL. The threat of a stun or other disable gives your champion a lot of zoning power because eating a disable very often leads to death. This is even stronger in 5v5 fights; the threat of eating a disable makes your team very dangerous to approach.
A slight mistake in positioning can often quickly turn a battle into 4v5 because someone got too close to the caster. Any approach towards the team must be made in full devotion; hit and running too close leads to death, retreating leads to death, etc.
3) For early-mid game power
The power shift in LoL isn't quite like how it is in DotA, but in general casters are quite powerful in the shift between early and mid game. Champions like Annie, Kassadin, and Fiddlesticks are some of the strongest gankers in the game at this point because of this. Mid game ganks can often lead to victories, so this is important. A note though, there are definitely carries and tanks who are also strong at this point in the game, so casters don't exactly have a monopoly on this (eg: Corki, Tristana, Shaco).
4) For AoE damage.
AoE is extremely important for 5v5 battles for obvious reasons. AoE is also good for pushing lanes. Note that casters don't exactly have a monopoly here either (eg: Corki, Nasus).
5) For the anti-carry.
With generally high burst damage, hard disables, and long range, a lot of casters are very good at playing anti-carry in team fights. Casters often lose against decently geared carries 1v1, but when the caster has a tank and other disables to help support him, he is in a very good position to screw over the carry.
The anti-carry role is very important. Consider this: a carry character's placement in the tier list has a lot to do with by how well they can deal with casters in 5v5 fights. For example, Twitch is currently tier partially because he outranges caster threat... Tryndamere is low tier because he gets disabled and nuked to death. That's how important a caster of that role is to the team.
So basically: having a caster on your team means having a low survivability unit that sucks at killing towers and often runs out of steam quickly, but brings extremely important anti-carry, control and AoE capacity to team battles.
There are some misconceptions about casters in LoL. One example of this is the argument that casters "suck compared to carries," because at most points of the game they will lose 1v1 to a carry. However, that's simply not true; casters in this game are top tier characters (and many carries bottom tier) and really cannot be replaced by carries in anything but a gimmick team.
Another myth is that casters become "obsolete" later in the game because of health/MR stacking and Banshee's Veil. This is only true in a very, very long game. Games at mid and high levels generally do not get to the point where casters become "obsolete." A character of any role becomes "obsolete" if he is too far behind in kills/levels/gear. For some casters, this is an advantage because they tend to have good kill records (eg: Annie).
So, like in the tank thread, I'll go ahead and make a quick runthough of the casters and their advantages/disadvantages. Note that I'm excluding AP builds of certain characters (Shaco, Sion, Nunu) and full supports (Soraka, Kayle) because they don't really fit what I've described above (well, Sion does I guess).
+ Excellent AoE damage control through huge AoE slows, AoE stun, and wall. Excellent survivability due to ult. Pretty good burst damage.
- Slowest movement in the game. Difficult to learn/master.
+ One of the best gankers at level 6, will 1-combo almost any champion at that point of the game if she had mid. Long range, high damage AoE stun. Stun has a "short cooldown." Very long range auto-attack and "free" nuke make her an excellent laner too.
- Vulnerable when stun is down. Somewhat reliant on ultimate to be dangerous. Short range on Incinerate makes it dangerous to deal full combo.
+ Great at jungling and laning. Very powerful 1v1 up to late game due to two CC's and potent life drain. Extremely dangerous AoE ult with surprise factor.
- Needs to keep up or else he's too vulnerable. Ult requires some setting up and protection.
Gangplank: More of a support caster
+ Probably the strongest single target nuke in the game. Very strong global AoE ult, good survivability and support abilities. Solid overall.
- Very squishy if built for damage. No short cooldown AoE or disable.
+ Early-mid game domination with ridiculous and guaranteed hit on rockets. Good AoE damage/Blind/stun on grenade makes him dangerous to get close to until later.
- Turrets are garbage, damage output becomes very weak later game.
+ Great global damage ult especially if he had mid. Very high sustained AoE damage. Wall is dangerous.
- No hard disable. Must get close for full damage output.
+ Good burst damage. Probably the best chaser in the game and one of the best escapes. Closest thing to a "caster carry."
- Extremely weak early game, needs to get ganks or very good farming to be effective later. Runs out of steam quickly. Needs to get close to do high damage.
Katarina: She's basically a caster.
+ Strong harassment/farming early game. Strong (but nerfed) AoE ult that can come from seemingly out of nowhere thanks to Shunpo. No mana costs.
- Got the nerfstick, hard. Ult is very counterable and her other abilities are pretty weak mid game unless she was fed greatly.
Morgana: Generally more of a support caster.
+ Black Shield synergizes extremely well with carries and champions like Nunu and Katarina. High AoE damage and dangerous AoE stun ult.
- Non-ult disable is a skill shot. No direct damage.
+ Dangerous on-demand stun. Ult gives a very sudden burst of huge AoE damage.
- Very short range on his high damage nuke and stun. Generally outshined by Annie.
+ Gate + AoE gives him extremely good map control. Gate + stun card makes him an extremely strong ganker. Global snare ult can be gamebreaking.
- Vulnerable when stun is down. Damage doesn't scale quite as well later on as some other casters.
+ Extremely high damage for a caster late game if he lands all his stuff. Anti-caster properties. A very good AoE stun that's also good to help with repositioning during team fights.
- His damage combo is not guaranteed and can be hard to land. Weaker than most casters until late game.
Zilean: More of a support
+ High early damage and range early game makes him a good laner. Ult turns anybody into a decent initiator. Haste practically spammable late game and a very potent snare.
- Generally outshined by true casters for damage/disables and by Kayle for ult.