First: Merry Christmas everyone.
Regarding Embers; I agree with you all that Zuko is getting a bit sueish and that team Avatar are getting a pretty rough deal but somehow I still like the fic, probably because of the world building.
I love the idea that Zuko is utterly terrified of the Avatar after the North Pole incident and that someone is questioning this whole 'four nations' dealy given that the colonies have been around for the better part of a century now or the idea that the avatar is going to be any better than Ozai if he's going to be channelling vengeful spirits right and left.
(Unfair to Aang but its not like anyone who thinks that really has the whole picture)
I like the idea that the Fire nation royal family might have dragon ancestry; sure its dangerously close to sueish if not actually crossing the line but it explains how the whole family is so freaking powerful and fixes some of the time discrepancies regarding lifespans while affirming that the Avatar world is heavily dualistic; they KNOW the spirits are their, real and powerful, the royal family having an especially strong connection to their nations 'spirit animal' works.
I like the idea that Zuko's scar actually fucked him up even more than the show let on; in a world of spirits and chi I like the idea that such an injury, inflicted with 'hot energy' could actually unbalance the way your own chi works, it provides a believable reason for some of Zuko's more boneheaded stunts while staying pretty close to the show and I can accept that Zuko is a bit out of character; its pretty clearly stated that his mental 'energy' has been flip flopping all over the place and only got worse in Ba-sing-say, something which is only just starting to settle down.
The author just using this as a big binary switch labelled 'lazy character development' is a touch annoying but not a deal breaker.
I especially like the exploration of different cultural ideas and reactions with Katara; she grew up on a freaking ice-plain populated by less than five hundred people, the idea that she'd understand what drives Zuko, much less react like us to danger or an aggressor is absurd and this is the first fic I've seen that actually sits down and explores the differences in the way the main characters work because of their violently different upbringings.
Still it really remains to be seen how the author will treat Aang now that he's becoming a major player, if he actually shows some of that backbone he had in the show all well and good but if he just rolls over and proves Zuko 100% correct than it pretty much stops being Aang and becomes a cardboard cutout used to show how awesome and 'mature' Zuko is.
Long rant short: okay so far, interesting ideas, skirting Sueishness but could still be saved.
As for an actual recommendation:
http://www.fanfiction.net/s/3862054/1/Sokk...the_Black_Sword
Sokka centred story told in the first person, may turn people off but the world building in this is EPIC building on hints and shadows within the show to create something utterly awesome.
Pairings: Aaang/Katara, Zuko/Mai and Sokka/Toph
It seems to have stalled, if not died, but what's there is well worth a look.