There is definitely strategy happening in PVP. Played with some small groups today, like 5v5 or so, some larger like 10v10. People use terrain to their advantage, kite people into ambush by guards or waiting stealth archers, suicide into groups to get a feel for enemy numbers, all kinds of stuff.

Personally I find Impulse spam to be one of the simplest things to deal with. One Sorc with negate can shut down their little pewpew train long enough to thin it out, especially if it is in tight quarters which is where this causes the most trouble. Or 2 or 3 people stacking oils at entryways tends to help as well.

In open field combat, range them, focus one target (communication required), and if all else fails, fall back and siege them. Try to kite their blob into a bottleneck where your team has the high ground, then boil them in oil!