Where to begin...
...first off. Reinforcement of the Army has been limited to one, so this build as-is is illegal.
Secondly, this deck is lacking in all the areas that Six Samurai should shine in: speed, aggression, and control over the field.
First off, where oh where is the Grandmaster? With your current build, you have no way to bring your Samurai effects online on your first turn, and that's already a huge disadvantage for you, especially since you're not even running the Enishi alternative. Absence of Grandmaster also weakens your ability to keep the samurai coming and recover from offensive pushes (which, I may add, you have no safeguard against, but more on that later on).You are also conspicuously missing two very handy members of the samurai family: Spirit of the Six Samurai and Hand of the Six Samurai. Spirit allows for some trickery with Double-Edged Sword Technique, buffs your other Samurai to help them swing over things while keeping their effects online, and pays its keep by granting you draw power as well. Hand lets you treat all of your Six Samurai like Exiled Forces, so I'm really wondering why it's not included. Shien is also awkward in a deck completely devoid of special summons (...why are you samurai not special summoning, come to think of it?) since you'll have a hard time ever getting him out on the field. Nishashi is a similar WTH choice. With a measly 1400 Atk, it's rather extremely lackluster. A.Forces sort of helps, but given you have basically no swarming ability, it's unlikely to be enough. Should be dropped in favor of cards that actually help the swarm.
Also, where are your three copies of Six Samurai United? Not running what is - for most practical purposes - a theme-specific Pot of Greed is a very, very questionable choice. And speaking of those, I see no Monster Reborn in your lineup. If the card is allowed (which it is) and monsters are played outside the context of an extreme graveyard-/special summon-hate concept then it should be in. Period. Reasoning is also your friend, given the wide Samurai level spread. Getting that lucksack monster out can still make all the difference. I'm also not seeing the appeal of Mage Power. You really don't have many S/Ts you'll want to keep around, and Samurai usually do die a lot, though they make up for the fact by being replaced or recurred, so equips aren't exactly their biggest friend. United We Stand if you must have one; at least then you are guaranteed a significant boost.
Most pressingly, however, your defense is basically not there. This is a day and age where weapons of mass destruction and beatsticks of 2500 Atk+ are common fare (courtesy of synchros and the big Ds) and you are very poorly equipped to deal with either. All your monster removal is of the destruction variety, so even a single Stardust Dragon can smack you around pretty much however it pleases. Your ways of recovering from opposing Lightning Vortex, Judgment Dragon, Dark Armed Dragon, Black Rose Dragon, and I-can't-be-bothered-to-count-how-many-others are also basically non-existent.
Long story short, when faced against anything even sort of competitive and up-to-date, what I see here would crumble fast. You need chainable defense (Threatening Roar is a good pick) to let you avoid game end through field nuke, spin or bounce effects to counter synchro (Phoenix Wing and Compulsory Evacuation Device would work well here), and preferably some assorted defense cards to prevent things from escalating to that point too. (Divine Wrath, Solemn Judgment etc.) Own synchro ability is always a plus, and could be afforded through a warrior tuner like Jutte Fighter or Rose, IF you first fix up the most pressing problem here.
Meaning the fact that you couldn't swarm to save your life. Unless you, through some unknown miracle, have assembled two Samurai on-field and a Shien in hand, the number of monsters this deck can summon per turn is precisely one and that's just plain pitiful for what is supposed to be an aggressive swarming strategy. Grandmaster, Enishi, Double-Edged Sword technique, do it however you like, but make sure that you can set off an entire chain of special summons as often as possible or any passable deck will wipe this one out before you even get started. Secondly, you need something to help you cycle through your deck to keep up and reach your key cards. Six Samurai United is the obvious choice, but beyond that, Reckless Greed and Morphing Jar are also solid choices for getting more cards quickly. Beyond that, you could go for the reverse toolbox approach (favors Double-Edged Sword Technique and Enishi, that), using self-mill cards like Ryko to rip through your deck and then pulling your Samurai back up with The Warrior Returning Alive or graveyard special summons.
...aaaand yeah, I think that's about it. It's been...ages since anything short of extreme control could successfully operate at this pace of play, you know, and this deck is sort of missing everything that made Six Samurai awesome.
