Mostly very mobile characters that get to the point very fast and ignore any defenses the defending team has set up. Turrets? Nope. Traps? Nah. Barriers, which some heroes revolve around? Nahh. These are comps spearheaded by Winston who annoys the enemy team with his huge size, health pool, and annoying barrier, which allows his other teammates to run in because the enemy team is focused on him. This lets both teams have basically a fair 6v6, where the defenders don't have the advantage of a choke point, high ground, turrets, mei walls, and barriers, all because the diving team just comes in like a wrecking ball. Matches are supposed to slightly favor the defenders, giving them the advantages of the high ground and all that, but taking all that away makes it super hard to defend, and makes a lot of characters not viable. Hell you can even have not dive heroes on the dive team like 76 who can get the high ground (which the rest of the team cleared for him) and get free damage in. And there's much more to the hell that is... dive. Tl;dr - a cancerous team comp that is very mobile and insanely difficult to defend against.

It's quite powerful right now. You just jump the healers with genji and Winston and you're good to go. It's also very annoying to play against.