When I was reading this I was like "I wonder what he'll say about engies. Probably like 'They are your free kills'"
Just one (or two) thing about engies in PvP:
Their DoT skills can kill even though the engineer is dead (That's how I managed to kill a nekkid pwnie)
Also not many players know how to use an engineer very good in PvP, but they know to kite or die. The only time an engineer is dangerous is in group PvP when they stab you in the back with their DoT's.