So, as it turned out, when I went to go put all my things in, I missed this part! Whoops. Here's the last bit, maybe the most important bit.

2: Shiva, Leviathan, Ramuh. What do?
No doubt at some point, are we going to get these three. Everyone's asking for them, they want them added. And I agree, I think it would be great to get new "Sapphire Leviathan", "Teal Shiva", and "Violet Ramuh", or something along those lines. What I -don't- want is for them to be simply reskins of the previous three gem-based summons. That would be a horrible waste of potential! Instead, give them all unique casts and Astral Flow mechanics. As an example, I think Leviathan would go great with 3 2.0 second cast, 3.5 second recast shenaniganry, with an enkindled OGCD that you press once or twice during it. That would leave the timing of Leviathan's "Phase" to be 10.5 seconds, very close to the existing 10.0, 9.5, and 11.0 timings of Titan, Garuda, and Ifrit. Unique casts and astral flows are what make the Gem summons interesting, so please expand on them! In addition, this is a great way to give summoner back some cast times, something that helps them feel more like casters!