I mostly agree with Intrope, in that it's helpful to divide the roles into Offensive and Defensive to aid understanding, but I'm not sure they divide as well into the individual/area groups like he said. My personal concept goes a little more like this:
Defensive side
Defender: Spot defense. It may be standing toe-to-toe with one big monster and keeping it right where the wizard wants it, or standing in a bottleneck and making sure that none of the horde of goblins can get past (At least not without taking massive AoO punishment), but this role focuses on claiming a small portion of the battlemap and controlling what happens there. This necessarily includes being hard to kill or move, and also having ways of dealing with whatever comes into your territory, both in a direct "hack-into-little-pieces" way and things like slowing movement or discouraging ranged attacks.
Leader: Party defense and boosting. Making the party better is the name of the game, either by healing damage or curing conditions, or buffing and other improvements to effectiveness.
Offensive Side:
Striker: Individual Target Neutralizer. Taking one specific monster out of the game, either directly by killing it or by applying seriously impairing effects. This includes either ranged attacks or high mobility, to be able to put the smackdown on your choice of monster rather than whatever's nearby.
Controller: This has been well-covered. Whether attacking a single target or a group, it's all about denying options and reducing effectiveness. Moving opponents around the map, making areas harder to move through, or just spreading a lot of damage around.
In other words, while I agree that they are divided by Offensive/defensive function, I would arrange the "terrain-based vs individual-based" axis with Defenders and Controllers being terrain (or "battlespace")-based and Strikers and Leaders being individual-based.
A couple other things:
Everybody's going to do damage. Defenders and Leaders have both been mentioned in playtest reports doing big damage. I'm fairly certain party-roles are the things you do WHILE doing damage, not instead of.
I've been wondering about pet classes lately, though. Will they be Controllers or Leaders or will they have them at all? Right now I'm guessing that expendable summons, basically any creature you don't have to keep alive, will be controller territory, while more permanent animal companions will be for Leaders, who will then have one more party member to heal and buff. Just guessing, though.
Defensive side
Defender: Spot defense. It may be standing toe-to-toe with one big monster and keeping it right where the wizard wants it, or standing in a bottleneck and making sure that none of the horde of goblins can get past (At least not without taking massive AoO punishment), but this role focuses on claiming a small portion of the battlemap and controlling what happens there. This necessarily includes being hard to kill or move, and also having ways of dealing with whatever comes into your territory, both in a direct "hack-into-little-pieces" way and things like slowing movement or discouraging ranged attacks.
Leader: Party defense and boosting. Making the party better is the name of the game, either by healing damage or curing conditions, or buffing and other improvements to effectiveness.
Offensive Side:
Striker: Individual Target Neutralizer. Taking one specific monster out of the game, either directly by killing it or by applying seriously impairing effects. This includes either ranged attacks or high mobility, to be able to put the smackdown on your choice of monster rather than whatever's nearby.
Controller: This has been well-covered. Whether attacking a single target or a group, it's all about denying options and reducing effectiveness. Moving opponents around the map, making areas harder to move through, or just spreading a lot of damage around.
In other words, while I agree that they are divided by Offensive/defensive function, I would arrange the "terrain-based vs individual-based" axis with Defenders and Controllers being terrain (or "battlespace")-based and Strikers and Leaders being individual-based.
A couple other things:
Everybody's going to do damage. Defenders and Leaders have both been mentioned in playtest reports doing big damage. I'm fairly certain party-roles are the things you do WHILE doing damage, not instead of.
I've been wondering about pet classes lately, though. Will they be Controllers or Leaders or will they have them at all? Right now I'm guessing that expendable summons, basically any creature you don't have to keep alive, will be controller territory, while more permanent animal companions will be for Leaders, who will then have one more party member to heal and buff. Just guessing, though.