War, ber, ranger, ber, healer. Will adding a bard or shammy do more for the grps overall dps then simply adding another berserker ? At what point does adding an adps class over rule or simply over dps adding another pure melee dps ?
Are you just going to stand and parse on a test dummy, or are you actually going to try and pull/fight stuff? Is this a box team, or actual people playing each class? If it's a box team, you're probably already losing quite a bit of DPS not really keeping up with rotations, and in that case, bard would be a *much* better choice as it could be largely an AFK character. Bard is a lot more than just added DPS, and the combo of a shaman + bard will do insane things to a melee group. 3 other characters getting hasted and procced > 1 more DPS. What are you trying to do exactly?
Adps is a literal joke in grp content it literally doesn't matter what so ever if your in a grp of real players stuff dies so dang fast now days it doesn't matter what adps is doing because they will not add more dps then a pure dps in that slot.
If you're fighting a target dummy, a berserker in that group will probably add more. Especially if you have a way to give you haste (ex: Enchanter with hastening of prokev). It won't be a huge difference though. For general purpose question a bard will improve your group the most. Not only will it increase the DPS of your group members, but it'll help the mana (by a tremendous amount) of your healer, increase your healing power (Rytan's Reckless Renewal), make your group run substantially faster with selos, give you a real puller (useful for solo pulling named through groups of mobs). You'll be able to pull more carefully, and also pull more recklessly/faster if you choose. When you have a group stacked with a berserker/ranger/warrior, pulling mobs quickly becomes increasingly important because wherever you go you'll probably start to have some long pulls. Bards (and other ADPS) make the game much more fun to play, because each character is so much more powerful.
