I can see that the basic plan is
1) Play big permanent facedown
2) Flip big permanent
3) Profit
I can also see that you've brought some of your own interesting ideas to the table with this build. The cards which bring back permanents when they die, such as
Kaya's Ghostform, are a particularly elegant touch for flipping big permanents, assuming you have enough sacrifice outlets to make them work.
I have a lot of advice to you, which I will give in the form of a few questions for your to
consider. You can, of course, disregard any of it that doesn't suit how you want to play the deck.
1) How much value are you getting out of your "bombs?"
It looks like you have a lot of big cards, but they don't synergize very well together. For example, you have
Omniscience, but you don't have a draw engine and a combo that you can use as payoff. You have
Surtland Elementalist, but you don't have a lot of high impact instants and sorceries that you want to copy. You have
Koma, Cosmos Serpent, but without an army of serpents it's sort of just a 6/6 indestructible beater without trample.
Another example is
Hornet Queen.
Hornet Queen was certainly a draft bomb in its day, but it's not terribly impressive in EDH without synergy cards. I play it in my
Kamahl, Fist of Krosa deck because the card becomes significantly more impactful when you
overrun two or three times, and I play it in
Esix, Fractal Bloom because you can make the 4 tokens come into play as additional copies of
Hornet Queen instead, for the memes.
I would recommend making everything a big bigger if you are really committed to this strategy. The Kadena, Slinking Sorceror came with a copy of
Apex Altisaur which I think would be excellent for your build.
Impervious Greatwurm and
Darksteel Colossus are much bigger indestructible beaters than
Koma, Cosmos Serpent.
Ancient Ooze can take advantage of all of your high mana value cards once you've flipped them up.
Avenger of Zendikar may have more impact than
Hornet Queen. I know some of these cards are expensive, but you can look for budget alternatives along the same lines.
2) What is your win condition?
You have a lot of big creatures, but not a lot of ways to get them through. It looks like
Kamahl, Heart of Krosa may be the only way that you are giving these creatures trample. I understand if you don't want to spring for
Craterhoof Behemoth, but there are budget alternatives. For example,
End-Raze Forerunners is often fairly effective.
Thunderfoot Baloth can also help you get your creatures through. If you don't want to spring for
Pathbreaker Ibex, you can actually use
Dragon Throne of Tarkir if you set it up with one of your huge creatures. I would make sure you have a clear vision of exactly how you intend to win, prune the cards that don't contribute towards that goal, and add new cards which synergize with that strategy. There is also one of my personal favorites,
Nacatl War-Pride, to ensure you get damage through. You can also go full-on degenerate and play
Blightsteel Colossus in the deck, particularly if you can flip it mid-attack somehow.
3) Speaking of synergy, it seems like some cards are in there to "check the boxes" rather than because they are useful in your build. If you have a ton of facedown creatures,
Ruxa, Patient Professor and
Muraganda Petroglyphs can be very strong. But if you are not going wide with facedown creatures, maybe these aren't so useful.
Ashnod's Altar is an incredibly strong card in the right build, but it's a bit underwhelming if you don't have lots of creatures to sacrifice to it. If you just need a sac outlet,
Altar of Dementia may be more effective if you have lots of big creatures, or just something like
Viscera Seer can get the job done.
4) You have a lot of high mana value cards. I know that the point is to cheat these in, but you always need to
consider the possibility that you may not be able to do so, and then you'll just be holding a lot of cards you can't play. You may want to
consider adding some more cards to cheat in your big beaters, like
Elvish Piper. You may also want to
consider adding in some morphs; just because you are taking Kadena in a different direction doesn't mean some of them aren't useful.
Root Elemental is a great card for cheating in your bombs and also getting your draw trigger off of Kadena.
Ultimately, you will need to decide what direction you want to take the deck in based on what you find to be fun, and what you find works with your playgroup. If you play in a low-powered group where everyone is just trying to throw bombs on the table, play janky combos, and not really worry too much about winning, that can be great fun and this deck could work great! If you play in a higher powered group, you might find that your reliance on high mana value cards means you are left behind more often than you'd like. I would personally
consider cutting cards that are just "known to be good" and instead try to build a more compact theme and strategy where you can create some fun synergies and combos.