There isn't an easiest, especially because we're going to be able to have 7 hero parties. While it's true that some professions are less powerful than others it's still completely possible for them to complete all content in HM without consumables. Weaker professions don't often get into groups though so if thats a big thing for you stick with whatever seems powerful at the time.
Anyway, as is the answer to all these questions, find a profession you like playing and play it. GW is a game; games are for fun. What's the point of playing a profession you hate just because it's less powerful than the other options?
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