This is a tricky bit to write, but also instructive, for me as well as for you.
You may not agree with the changes I make, but generally, I'm really happy with my decks and their performance, so cards tend to represent upgrades rather than total reworkings.
I have to say that so far, I'm not overwhelmed by the five legends--I haven't felt the urge to build one of their decks...yet. :D
Also, I'm one of those people who trades hard at prereleases. I want to get rid of things that have a high price tag ASAP, and hopefully get other, more-stable-value cards. This is one of my tricks for having 15 EDH decks and not bankrupting myself.
Oh, and Transguild Promenade is going into just about any deck that's three or more colors. That's just a given.
In: Jarad, Golgari Lich Lord, Guild Feud
Near: Cryptborn Horror, Deathrite Shaman, Utvara Hellkite
Out: Hamletback Goliath, Hibernation's End
In this deck, with 61 creatures, Jarad is going to be huge until I get Rest in Peace cast on me. Guild Feud is a ridiculous win of a card for this deck, and I can't wait to cast it, I really can't. Hamletback has been ok, but rarely good on his own. Hibernation's End is one of my pet cards, but the Feud is also going to get me a creature each turn, and be much higher-impact. I feel like Deathrite is not as good as the other graveyard answers I'm running (Withered Wretch, Nezumi Graverobber) and I haven't felt like I need more. The Horror may be amazing, but Hamletback is probably more consistent (though Horror does have trample) and I'm not playing enough Dragons to make the Hellkite an option.
Animar, Soul of Elements
In: Guild Feud, Utvara Hellkite, Worldspine Wurm, Niv-Mizzet, Dracogenuis
Near: Faerie Impostor, Mercurial Chemister
Out: Mwonvuli Beast Tracker, Heartwood Storyteller, Whispersilk Cloak
I want this deck to take advantage of the many flicker effects I have, and maximize the colorless mana costs involved. I'm reserving judgment on Niv 2.0, because I want to hit and I want to draw a bunch of cards, but the UURR may be a bit much for this deck. This is another deck where Guild Feud gets to shine, putting big creatures into play on the cheap. Imposter's bounce might be nice, and the deck could probably use a lowering of the mana curve, but I don't think it's enough. Chemister is very tempting, but I'll hate discarding big creatures to kill big creatures. (I want to play those creatures!) Tracker has never been a favorite of mine, and Storyteller triggers off of 15 cards in the deck--more than I want. Cloak is nice, but the shroud has caused some uncomfortable times for this deck.
Azami, Lady of Scrolls
In: Cyclonic Rift
Near: Conjured Currency
Out: Spell Burst
The Rift is an amazing card, one that will blow a game wide open after I've spent a turn or two stealing creatures. (If I control it, it dodges the Rift!) I like Currency, I do, but it's likely to be used against me, having someone exchange Currency for a Control Magic I cast on their creature. Spell Burst seemed like a good idea, but I never had the mana to buy it back.
Balthor the Defiled
In: Grave Betrayal
Grave Betrayal seems custom-made for my Zombie deck. I really will enjoy killing everything and then bringing it back on my side. Nefashu has been inconsistent for me, and frankly, too expensive. An easy swap.
Garza Zol, Plague Queen
In: Necropolis Regent
Out: Blood Seeker
This is both a Vampire tribal deck and a Grixis control deck, and none of the sweepers in this set are good enough. Blood Seeker has never been amazing for me, and the Regent, plus Garza herself, seems like an incredible card for the deck.
Kaalia of the Vast
In: Angel of Serenity, Rakdos, Lord of Riots
Near: Desecration Demon, Grave Betrayal, Utvara Hellkite
Out: Sudden Spoiling, Brightflame
Angel of Serenity is going to do all kinds of handy things for me, likely involving my own graveyard. Rakdos seems vastly overpowered in a deck like this--he'll be cheated into play with Kaalia's attack, and in the second main, let me cast overcosted creatures for only their colored mana. Desecration Demon is likely underpowered in EDH, Grave Betrayal is something I might come back to, and the Hellkite has too awkward a trigger for this deck. (Let's face it, if I'm attacking with Dragons, I'm going to win anyway.) I'm taking out two cards that covered token decks well, but I feel I need to add a little to the 'beat face' plan, and this puts me up to 39 creatures I can drop in with Kaalia.
Near: Death's Presence
I like Death's Presence in a deck dedicated to +1/+1 counters, I really do, but the problem is that this deck is already soft to mass removal, and that's what will trigger the Presence the most often.
Nin, The Pain Artist
In: Izzet Staticaster, Mercurial Chemister, Niv-Mizzet, Dracogenius
Out: Tahngarth, Talrumm Hero, Magma Phoenix, Crimson Hellkite
I knew there'd be at least one great pinger in the Izzet guild, but all three are going in. I've got every deathtouch-granting equipment in this deck, so Staticaster can do some serious work against token decks. Chemister will probably just be there for card-drawing, but can also kill some bigger things if I have no deathtouch handy, and the new Niv is just amazing. I've never been too happy with Tahngarth, him being a 'fight' instead of a ping, Magma Phoenix costs too much to recur (and I've got Shard Phoenix in here anyway), and Crimson Hellkite is easily the most expensive pinger ever.
In: Collective Blessing, Growing Ranks, Vitu-Ghazi Guildmage, Chromatic Lantern
Near: Trostani, Selesnya's Voice, Wayfaring Temple, Phantom General
Out: Sigil Captain, Goblin Assault, Geist-Honored Monk, Everflowing Chalice
Blessing is pretty much perfect for this deck, which can churn out tokens with great ease. Growing Ranks may be underpowered here, but free tokens are generally very good for this deck. The Guildmage is really going to be a star here, especially if I get Training Grounds in play--Populating for GW seems tremendously amazing. Since this is my only 5-color deck, it gets a lantern. Trostani is a card I may come back to, Temple isn't really good enough without trample, and Phantom General is a fun effect on a fragile body. Sigil Captain actually didn't trigger as much as I'd hoped, Goblin Assault was rarely worth it, the Monk really wasn't either, and the Chalice rarely got cast for more than 4.
My other six decks...I'm selling. I'm not really bothering to keep them updated. The exception was Rest In Peace--that was too perfect for Mangara.
If you want to see the decks for sale, lists and prices, go here.