Not sure how to really make use of that Sakashima... However I do love the art. I guess you just build a deck that can make Clones and Token copies of really good legendary cards?
There's two big directions I can see, which can obviously overlap. One is taking advantage of the Mirror Gallery effect in the command zone, and playing a lot of legendary things you'd like to copy (and copy effects) to stack their abilities. The other is to plan very specifically to copy your partner commander, and double up on whatever value they represent. Partners like Kodama of the East Tree or Vial Smasher the Fierce are obvious options, but there's relatively few partners that wouldn't get some benefit out of having a second copy on the battlefield.
some friends are saying sakashima himself is potentially broken, if not now then later... and frankly i'm just not seeing it. he's cute. he'll make for some fun interactions. i don't think there's much of anything i necessarily want to partner him with currently, like nothing screams but you could have two of these! he'll be fun and i think builds with him will be more interesting than broken.
the cascade guy... i don't like because its restricted to entered play this turn. that means its generally going to be a smaller creature that you played first, or you got lucky with your cascade and didn't hit a sol ring, or you set up the top of your library probably with green... its cute but nothing special. it really should've been sakashima's student instead.
I like Sakashima’s Protege more than Sakashima herself (himself?)
In its truest form, Sakashima is gender-neutral and species-fluid.
It can be anything it wants to be, even another unique, legendary creature.
Failing the role of the imposter, Sakashima is a 3/1 vanilla whose intent is to strip away the unique identities of others who can't change who they are as easily, making them easier to impersonate.
Mechanically, Sakashima and the protege are good, and I've already ordered my foils before the price jump.
Any serious commander player should probably do the same and lock them in at the earliest available opportunity.
Sakashima will be great to pair with several partners, including those in the future, and first prints will be worth a lot more than you can get them at now. Yes, the same could be said about many new cards as they enter the meta and establish themselves, but this starting in the command zone with another tool and thinning the deck to 98 makes a big difference on its own. What better way to improve your opening hand than filter out a card and start with an extra clone at your disposal? I'm certainly not an expert, but in my opinion this card in commander borders on what Lurrus' power level was in standard before companions were hosed and the new tax was implemented.