So, we learn a little bit more about fusions, in this episode, as well as how the temple seems to be able to work.
On the temple. It seems like any gem or any fusion that is 'keyed' into the temple has a room designed accordingly to how the gem wants it to be.
For fusions. They are fusions, but absolutely their own person. Yes, Single Gems do have the memories of the fusions, and fusions contain the memories of the singles. They seem to be like two and two-thirds of a person mashed into one body.
Fusions, in addition to the weapons and abilities of their single components, also have unique and amalgamated weapons and powers. Garnet and her future vision is a testament to that, as Sapphire's vision is straightforward, Garnet's reflects Ruby's spontaneity, and all of the possible branding paths one could take.
Fusions seem to be centered to reflect on the specific high point between two gems. Garnet's theme is future, and how Rubles and Saph balance out directness and fluidity. Sardonyx seems to take in the prim and proper of both Pearl and Sapphire, while also being blunt at times, as Ruby can be. There are a number of reasons that Smoky could exist, but I think their theme is originality.

Also, isn't it interesting how, after reflecting on Jasper's corruption and fusion with the corrupted gems, we learn how Gems fuse through these high points?

I don't know about originality...In my opinion...
Right before Smokey fought Jasper, Amethyst accepted that she couldn't fight Jasper alone, and Steven was there to help. Not to mention that after the breath test that Sardonyx gave her, Smokey was talking down on herself.
So maybe their thing was teamwork and/or humility?

Possibly, but I still stand by what I said. Both of them are defects in some way or another. Amethyst sat too long, and Steven is something that had never existed before that lives in the shadow of his dead mother. Both of them can't do the job that they're intended for, and make up for it in unique and unorthodox ways, while still remaining true to their characters and reflecting on what they want to be. Smoky Quartz is another progressive step in both of their lives, using their imagination and child-like attributes to turn a toy into a weapon, her lack of knowledge when speaking to Sardonyx (which I think was mostly Garnet, who had that reaction the last time Steven fused with someone new), and how Steven and Amethyst push each other to be more than the path laid out for them

Ah, I see where you're coming from now. ^_^

Looking at from that perspective, it also helps explain why fusions like Sugulite and Malachite don't work out as well. They're born of more negative emotions than other fusions, as well as lacking any reall high points when they come together. Thus, the fusions come out monstrous, dangerous, and with a tendency to take over the gems within them(a problem that doesn't seem to happen with the other fusions). This also makes me wonder if the emotional state of the two gems while they attempt to fuse could possible change how they look, or even what kind of fusion they become? If Amethyst and Garnet were to fuse again, for example, would they still be as unpredictable and dangerous, or would Amethyst's more mature nature help calm them down, possibly shifting their form to one that is less disasterous.

Well that's the question now, isn't it. We've seen that reforming gems change the appearance of the fusion a little, and given what we know about fusions, I think it's safe to say that, while at the foundation, they might not be changed, but the fusions will be a little more wary of such things.

and man I need Nikki bad slaying more gem monsters

I really liked today's episode, it didn't seem to have a whole lot of 'deep' things going on in it but it was wicked to see the fourth wall breaking and Sardonyx and Smokey Quartz hanging out. Also @pyroman, Garnet also has some electricity powers that she never uses thats a mixture of Ruby's fire powers and Sapphire's ice powers too, not just the future vision.

SO THE NEW VOLTRON, RIGHT? THE OLD TEAM IS NOT THE NEW TEAM. SHIRO, WHO WAS KNOWN AS SVEN IN THE ENGLISH OF THE ORIGINAL, IS NOT THE LEADER, AND HE IS NOT DEAD, HE'S PRETTY COOL. Note, all of the colors actually line up this time around. Keith Pilots Red, Lance Blue, Pidge, Green, Hunk, Yellow, and Shiro Black.

SO BACK TO THE YELLING. SHIRO IS COOL. He's not the edgy dad he looks like from promo shots, he's just a tired dad who wants to catch a break for like point zero seven seconds. Plus, he's like the oldest, since all of the other Pilots, known as the Paladins of Voltron, are all teens.

Lance, ladykiller. fucking dork. Yeah, the Sokka in Space character. He's cool, he's funny, he's like captain kirk, but younger and funnier. He hates Keith, proclaimed him as his rival back in school, even though Keith has no idea who Lance is.

Then you have Keith. He has no idea who Lance is. I guess you could call him Space S3 Zuko, but nicer, and with a bigger pinch of outcast. slightly edgy, but he's pretty cool, and he and Lance have some brother moments.

Hunk. Big, hungry, engineering whiz, also a dork. and gentle giant with a passion that burns with the slow cooking intensity of a wok.

Pidge. Small, brainy, smol. Pidge has his reasons for doing as he is, and is a little more selfish, but he does address his problems when they need to be addressed.

And you got Allura, the princess of Altea, and the current monarch of the Castle of Lions. She's more than a damsel in distress, and is pretty badass.

Coran, Coran, Coran. He's the big doofy uncle who doesn't exactly understand what's going on around him, but he tries, and that's all that really matters.

and there you have the main voltron Crew, who get whisked away from earth to become the defenders of the universe, whether they like it or not.