In the old maps I notice people tend to run from one mob to another.

The new maps tend to discourage that. Dead city area will have undead meteors, risking seperating tank and squishy members, if you're not careful. You always have to keep moving. Before you know, you are standing on a toxic pool and you die.
Smashing pumpkins (exploding) are like a speed bumb.

Also I think you need more cooperation now. At tombs IV for example, it is better to clear the outer areas, so easier to join group if you respawn (die). So you need to agree with your mates as how to clear the level.

Anyone agree on this?