Well, let's dare to compare. Here's dand's Samurai Fighter archetype.
dandwiki.com/wiki/Samurai_(5e_Archetype)
First, the stances are a good idea fluff-wise, but
>You can use a bonus action on your turn to enter a stance if you are wielding a melee two-handed weapon. The stance lasts for 1 minute, until you change stance or until you are knocked unconscious.
So I can grab a two-hander, enter a stance, then drop my two-hander and keep my stance? Seems a bit silly.
There's also nothing to say how often you can enter a stance, so I guess you can enter them all day long, so why last 1 minute? I mean, I guess stances eat a bonus action (reaction later on) every minute (or when you swap) but it just seems unnecessary.
The stances, mechanically, are pretty broken. You can deflect projectiles free of any action cost just by hitting a 16 AC, on top of Disengage as a bonus action? Overpowered.
Stone stance isn't very good and is poorly worded: are the enemies the ones 10 feet from you, or are the allies the ones 10 feet from you?
Fire stance has them making contested rolls whereas water stance has enemies making a roll against saving throw DC (which is weirdly worded). It's inconsistent.
Unlimited frightens (that last "until you end the effect," so if the effect ends on its own, guess they're just perma frightened) for a bonus action? OP.
Considering how often a fighter can hit you, water stance is going to force a lot of saving throws (compare it to Monk's Open Hand, where the most you can ever do with that is two a turn, and only if you choose that effect for both).
There's also two stances that give +2 and -1 to AC, which kinda goes against the game's design philosophy of not having a bunch of pluses and minuses to juggle around.
And this is just scratching the surface. Seriously, this is supposed to be better than the Unearthed Arcana version?