My class makeup is SK, Fury, Wiz, Illy, Conj, Troub. It is primarily a ranged based team. Only the tank needs to be in melee range and the rest can sit back and dps. I tried speccing a warden melee and converting the illy to more melee based but a lot of fights there is aoe's that you need to joust out of or avoid completely. It is just so much less hassle being able to dps from afar and still maintain good damage. On a lot of fights you can position your team behind a boss and go to town, but for every 5 of those, there will be a boss where you need to joust or move away and I want optimal uptime so no melee for me, although they do a lot of damage.
Second issue with melee is they are extremely dependant on auto attack swings, while casting isn't.