What you choose to do is dependent on what types of support your friends need. If you are doing landscape questing together, you can safely choose a DPS spec for any character. When you are doing solo quests in a group, you'll generally go through it like a hot knife through butter so very light healing is all you'll need. All 3 of these classes have base healing skills that are available to all specs, or skills that are very low in the healing line that you can access if the base skills turn out to not be enough.
Originally Posted by UnknownSoldier
The only exception MIGHT be Minstrel; one of the folks in Beta was of the opinion that the main healing line had enough Tactical Mastery to represent a viable solo spec. Solo specs would work well for your group in Landscape content, so if you choose Minstrel you might want to try that out.
When your group decides to do group content, you can change your spec to a healing focused one. Each class approaches healing differently, and that hasn't changed TOTALLY in Helm's Deep. If you read the skill descriptions and think about how you typically play, you can usually tell what you'll need to change to act in a healing focus rather than your typical play style.
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