I drafted a lot of 3xTHS lately but I had never tried sealed so yesterday, I was looking for something different and tried a sealed. I joined without any expectations but I didn't want to go 0-3 which I did. I don't think my pool was really bad but maybe I built it wrong. Any opinions would be extremely valuable.
I can't really see anything that stands out as a stronger alternative to the GW deck you built. You might be able to tweak your original build somewhat; Pheres Band Centaurs vs an 18th land, for instance, but you have the Caryatid so it might not be necessary.
Maybe splash for Sea God's Revenge? That card is pretty nuts. Maybe drop Fade from Antiquity for SGR, drop Centaurs for the Unicorn? Nah, you're deck is pretty focused, and there's not really a compelling reason to screw with the mana consistency. I'd consider siding in the Revenge if my opponent was a slower monstrosity-style deck, maybe.
In the future, it helps a lot to segregate your cards by color. It makes evaluating the pool easier and you'll get more constructive input that way.
I think Sea God's Revenge might have been ok. I considered blue and red for a very long time due to Thassa and Stormbreath. Glad I made the right choice, but that must mean that I played really bad then.