let me just start by saying that the new infected is lots of fun, but the one thing that I would like to see is a double boost for the zombies or a 25% speed increase. infected in past games seemed to strike that fear into you because they were so quick.
They need to be faster.
well I also thought they would be too slow. But the infected need to attack together, than they will get the survivors. After a couple of games, I think the speed is good. you need to act clever and together with other infecteds.
I think the idea is to swamp the enemy zombie style, the speed works in that regard