Don't get me wrong, I respect all the Six Samurai players, including Junior Dorcin, Oscar Zavala, Sean Coovert,... You need to be a good player to do the correct combos with your given hand. The luck-based side is that, if you don't draw well enough, there's nothing you can do.
I'm not talking about luck today. I'm talking about the deck when it goes like expectation. What makes it good?
Shi En is a spell and trap negator, which is always good. 2500 is respectable in his era, but not now. Boss monsters (the Dragons, Master Hyperion, the Chaos duo) and especially the easy access to extra deck without using spell and traps (Tour Guide, Wind-Up, Machina Fortress, Summoner Monk...) make it easy to have a bigger beatstick on the field. Destroying Shi En is a little bit harder since Shi En has the ability to dodge destruction effect, and he has Magatama Musanaki as his backup.
However, Shi En is not all in that deck. Shi En is, as always, the boss. But the boss, as always, has his assistant.
- Hand of the Six/Mizuho: The destruction effect seems no dangerous at first glance, until you see it combined with Gateway.
- Legendary Six Samurai - Enishi: Don't ever underestimate this card. He has the ability to get rid of any monsters that belong to the extra deck. His effect is a quick effect, thus if you Bottomless him, he can kick himself to the hand and next turn will be no different.
- Heroic Champion Excalibur/Blade Armor Ninja: In the long run Six Samurai may not have enough resource to keep up with any deck of the current meta. However, they have the ability to push very hard (even without Gateway). 4400/4000 + 2500 is 6900/6500, no joke here! You may find yourself near death very often, and if you cannot push through everything the following turn, gg.
- Kageki + Shadow of the Six: 3500 (Kageki) + 2500 (Shadow) is 6000. No joke again!
Let's take a look at Chaos Dragon: Charge of the Light/Solar Recharge is denied. What will you do? Nothing looks effective against Samurais' field, from Ryko to Zenmaines. Or Mermails. You have no access to Abyssphere, so what if your Undine eats a Warning? Nothing you can do because even if you have Abyssmegalo AND Heavy Infantry (commonly run at 2 each), you have to get rid of all the other Samurais before touching Shi En (Megalo is smaller than Shi En if you do not realize it). No easy task. And what will Evolzar Laggia/Dolkka do against Shi En assuming no Forbidden Lances?
The real power of Samurais comes from turn 1-2 plays. If they go explosive turn 1 and you cannot break through, there's a high chance their turn 2 will be your last unless you play an incredible amount of traps. No matter how fast current metas are, people have 1 normal summon a turn. If you can't make use of it, or your opponent just doesn't let you, it's bad.
Side story: Today I picked my Samurai deck against Wind-Ups. I went first, ending my field with Gateway, Kizan, Grandmaster and Shi En, setting Bottomless. My opponent MST'd the Bottomless (I let it go because I feared Dark Hole or any power spell), then go Shark Magician into Tiras and Utopia. Utopia killed Grandmaster, Tiras killed Kizan and Gateway. Second turn, I searched for Enishi with ROTA, and as soon as my opponent got to his draw phase, his field was cleared. He sacked Rat from the top, made Acid Golem and killed Shi En (I have no Samurais in grave to feed Enishi T_T). My turn, I dropped Dojo and Mizuho, forcing out Torrential. His turn, he sacked a second Rat and make Zenmaity + Gigabrilliant to wreck me. My turn, I topped Elder (with an 1-counter-Dojo), make Catastor and killed Zenmaity. He flopped Rabbit of the top, summon it, pumped it to 1700 (and Brilliant to 2400), ended. I killed Brilliant with Catastor, set Double-Edged. He passed. I sacked a Kizan and Double-Edge for Shi En + Enishi into a field of Catastor, Shi En, Blade Armor Ninja to stole the game (Enishi cleared his Rabbit)
Like I said, getting Shark Magician'd and field cleared is not the end for Sams.
So, watch out!
And thanks for reading xD