a team of 6 already makes full use of all 4 main roles?
What game are you playing?
There are 4 roles in this game: Offense, Defense, Tank, Support. In both competitive and casual, most teams have at least one of each. Am I missing something?
Yeah? I looked over some recent games from the league and most teams are still 2O2T2H.
Because "Offense" and "Defense" is a fairly meaningless moniker that is mostly there to give the new players some sort of an idea as to what the classes are, and in this case, Offense refers to mobile characters with dueling ability and Defense refers to more specialized characters with area denial abilities. It's still not that useful of a distinction though because Widowmaker and Hanzo, for instance, are superior picks on Attacking the first point rather than on Defense in general, since on Attack in a regular 2 Control Point map, the distance you have to cross to return to the contested control point is shorter for the attackers than for the defenders, and the "sniper"* classes excel at scoring picks even if the rest of their skillset is theoretically poor at storming the front or doing mop-up. Widow in particular is also kinda shit at holding the last point because you're confined to defending a large area that you can't often confidently snipe in and she also doesn't do much in the event of a full 6 ult pile-up from the enemy team (Hanzo can at least ult the cart to deny capping attempts), all centralized on a single location (unless she can make up for it with amazing skill).
I'd advise to generally ignore those distinctions; they're mostly hints rather than set-in-stone definitions. D.Va and Roadhog are also tanks, for instance, but they fulfill much different roles than other tanks. The game doesn't distinguish between the "anchor" tanks like Rein and Orisa and "dive" tanks like Winston or D.Va, and it especially won't tell you that a solo pick Roadhog or Zarya might not be a sufficient barrier for your entire team in case you're stuck in another 1T1H4DPS team composition. Same with how Symmetra is the only "Support" character with no heals and how dubious it is that she doesn't share a hero class with Torbjorn, who has a similar skillset (area denial with turret + bonus survivability to the team).
*"Sniper" is also poorly distinguished by the game. Having a healer Ana in the team with Widowmaker isn't "too many snipers", because Ana is simply a healer who heals with bullets.
