Every class fulfills every role in a slightly different way. Thus which you prefer is mostly down to preference.
Take the healer role for instance. Templars make for strong burst healers. Sorcerer are unmatched when it comes to sustained healing. Nightblades are siphoning healers that heal and do damage at the same time. Dragon Knights are support healers with a plethora of group buffs and AoE CCs.
While I might think magicka regen is important for a healer role, you might think stamina is most important. Nothing wrong with that, just different play styles. You're gonna pay your 15 bucks a month to play however you damn well please, thus, I suggest looking at those passives and picking what fits YOUR play style rather than following what everyone else is doing