I haven't play tested the deck officially yet, and I still have a lot of options there to consider in the sideboard. But this has been honed down to a starting place.
The deck centers around Marath - his abilities rock and he juste stronger the more times he comes from the command zone. Now his abilities are mana intensive and they are fueled by +1/+1 Counters. So I have structured the deck around +1/+1 counters. The core of this deck is around cards like primal vigor, doubling season, archangel of Thune, etc. All of these increase his potency and his size. Now that he is fueled he can do a lot of different things - when he is equipped with death touch you can ping other peoples creatures to kill them with things like basilisk collar, and gorgon head. You can move counters to other creatures to draw cards, kill enchantments, lands, and artifacts, or to fetch lands with cards like fertilid and shine wend. A third dynamic is that of generating creatures. The purpose of the token creatures in this deck is to generate mana (ashdod's altar), deal damage (purphoros), or generate more counters (cathar's crusade). But in addition to these, since they are weak they are great for devouring for the bigger creatures like mycoloth, and prey seizer dragon.
Now, there are a lot of creatures that just get huge because of their generation of +1/+1 counters - Taurean Mauler, Retaliator Griffin, etc. These obviously can't move their counters by themselves. So cards like Ion Storm, and Ooze Flux allow you to create creatures and deal damage to creatures and players with all that extra counter space.
Now, there are probably some other ways you could take this deck, but this deck is really a middle of the road aggro deck, with tons of utility to clear the board of obstacles (creatures - Deathtouch, Artifacts & Enchantments - Aura shards & +1/+1 Counter creatures), so that you can either beat them down with a big flying creature you had use devour to get huge, or you can roll them over with big creatures from the counters, or just make Marath huge and swing that way.
Anyways, that's some of my initial thoughts, let me know what you think.