RWB?

So I think there are a few issues here, but first:

1) Is this for FNM play?  If so, how competitive is it at your FNM?  Are we talking all tier 1 decks or are there plenty of home brews?

2) What's your budget to improve the deck?

Now, for the deck itself:

Most importantly, you need to choose the strategy as it's currently split between something sort-of aggro and a more mid-range deck.  Trying to saddle the line between the two seldom ends well.  You really need to pick one and run with it.

I don't know that either strategy is ideal, as it has yet to be seen whether the tri-colored "clan" decks will be worth anything or not (it would be a shame if they weren't).  As it sits, I'm not sure about Athreos or Iroas for either build and you'd be better served with the appropriate fetches and Mana Confluence - at the moment you're sitting on 15 land that come into play tapped.  You would also do well with more land outright - Aggro typically can get away with 22 lands and a curve that tops at 4, mid-range needs roughly 24 lands but can have things at 5-6 play reliably.  As it sits you only have 22... so that would suggest an aggro deck, but then you would want to drop quite a few pieces.

So the tl;dr version, pick either aggro or mid-range and really focus in on that strategy more.

If you're going aggro, you want UNTAPPED lands and low CMC stuff.  There is even potential for a semi-warrior tribal build.  Here's the list I've been tinkering with:

23 Lands:
3 Mana Confluence
4 Bloodstained Mire
3 Battlefield Forge
3 Caves of Koilos
3 Swamp
3 Mountain
2 Plains
2 Urborg, Tomb of Yawgmoth

29 Creatures:
4 Bloodsoaked Champion
4 Tormented Hero
3 Soldier of the Pantheon
4 Chief of the Edge
4 Borderland Marauder
4 War-Name Aspirant
2 Grim Haruspex
3 Goblin Rabblemaster
1 Iroas, God of Victory

8 Other Spells:
3 Sorin, Solemn Visitor
3 Ride Down
2 Mardu Ascendency

What you'll note is that almost every creature is a "warrior" subtype AND they largely top out at 3 CMC.  To be honest, I've been thinking very much about cutting Iroas from this list as he has frequently underperformed.  So you have 11 one-drops, 12 two-drops, 7 three-drops (if you count the ascendency which you cannot discount, this card is sick), and 3-4 four-drops (depending on whether you keep Iroas).

I can't say I've tested this extensively, but it has done rather well when I've run it (and the mana have behaved).  Having every land enter play untapped is also great.  Ride Down is an absolute monster with Rabblemaster as they'll often try to chump him or block with a Courser to trade... no such luck for them, as you remove their blocker AND get a load of damage though (this doesn't work on Caryatid, but if they're blocking Rabblemaster with one of those, well, you're doing alright there already).

At the moment the SB is as follows:

3 Butcher of the Horde
2 Sarkhan, the Dragonspeaker
3 Utter End
2 Hero's Downfall
2 Stormbreath Dragon
3 Thoughtseize

Why these cards?  Well, to be 100% honest, it's not entirely clear how well an aggro strategy will fare in the new standard environment.  One issue is that the opponent will be able to side in mass removal in the forms of Drown in Sorrow and Anger of the Gods, in an effort to counter this and catch the opponent totally off guard, you can use this SB to transition almost completely into a mid-range Mardu build.  To the Spikes out there, I know this is not optimal, but one can't really have an effective SB without at least some inklings for what the new meta will look like.

Anyway, this is clearly the optimal list which would be worth like $500... but it'd be something to shoot for.

So if you're looking for a more mid-range strategy, you typically will want more removal and a lower density of threats (but with those threats being, well, more threatening).  So if you'd prefer a Mardu Mid-Range build, I've been tinkering with the following list:

3 Temple of Triumph
3 Temple of Silence
3 Temple of Malice
4 Bloodstained Mire
3 Mountain
3 Swamp
2 Caves of Koilos
2 Battlefield Forge
2 Urborg, Tomb of Yawgmoth
4 Goblin Rabblemaster
3 Crackling Doom
3 Mardu Charm
3 Thoughtseize
3 Butcher of the Horde
2 Sarkhan, the Dragonspeaker
1 Mardu Ascendency
2 Utter End
2 Hero's Downfall
3 Anger of the Gods
1 Elspeth, Sun's Champion
3 Magma Jet
3 Stormbreath Dragon
2 Chandra, Pyromaster

Sideboard:
1 Deicide
3 Despise
2 Stoke the Flames
2 Chained to the Rocks
2 Drown in Sorrow
2 Banishing Light
3 Nyx-Fleece Ram

So what you'll notice about this build is that it is aimed toward a much slower, longer game.  Whereas the aggro deck is built to literally crap creatures onto the field, this one has a lot of emphasis on disruption, removal, and versatility.  Most players don't run Anger mainboard, but rather than be caught off-guard against aggro and ramp decks, I prefer having the option there.  You can use it to easily take out a fleet of aggro stuff or even to drop your opponent's mystics and caryatids - nothing is more back breaking for a green deck than losing 2-3 rampers on t3.  You have more pointed removal in Magma Jet, Utter End, Hero's Downfall, Crackling Doom, Mardu Charm, and even Thoughtseize.  But you'll note that ALL of these cards play multiple roles in the game plan, i.e., Magma Jet which can burn a player/PW, torch a critter, or just be used to fix your upcoming draws with the scry.

How does one win the game here?  Well, through a battle of attrition AND some major threats.  Goblin Rabblemaster just craps card advantage.  Chandra can give you added cards.  Stormbreath is often a win on its own, and, if not, Sarkhan and Elspeth are happy to clean up too.  So again, the challenge is to make it to the mid-game at which point you will just dominate.

I'm not going to claim that this build is ideal, but it has a lot of options.  The true control deck for the post-rotation format has yet to really be defined (or really even be attempted that much).  The simple fact is that control has relied on Supreme Verdict and Sphinx's Revelation for so long that control players have to remember what they were doing before RTR came along.

Anyway, I hope something from these builds makes sense.  I can provide more clarification on card choices if you like or if you're more interested in the decision process behind why one would go with an aggro deck versus mid-range versus control.

Good luck!