I really think they set the win-ammount rather low for eldar, as the population also was quite low for them. And you have to keep in mind, a lot of eldar players may have been lured in again, to reactivate guilds and whatever to win their faction goal.
Eldar are hard to play, but once you master them, they scale rather high up. That's what i learned from playing them. Once you are in your zone, you instakill left and right, but if you charge into the wrong situations, you also die instantly, something you can somewhat evade with other races
And after how chaos painted map red I don't want to hear any Conviktus whine about anything being stronger then chaos is.
But not a Vengeance Storm Bolter, certainly there's a reason basically every Space Marine who can uses it over the regular. It appears to be a straight upgrade.