I know what you mean. The best example is how people simply power-leveled their characters in single player to be max rank much faster. What took me over half a year, they did in days.
But it's not about Quests as a specific solution. My general approach is to give people more reasons to play in likable ways. And with that being said, there is still ways to enforce healthy rules.
I mean, as much as i love to see 6 Chompers going completely ham in one match, or 8 Super Brainz jumping all around - it gets old when it happens every third match. And its with no surprise the Imp who causes most of these problems. So technically each class could be restricted to 3 per match. Or anything like that.
But GW2 even fails to inform the players about what a healthy team is. Overwatch for example tells the players their team does not have a healer, or tank.
Popcap simply made a lot of mistakes in their general design. Having a funny chaotic game is one thing. But people playing as a team and approach certain things with a couple thoughts beforehand is something completely different. And yes, that needs more than a couple Quests. But they can help.
