You made pretty good choices with a lot of your creatures man, lotta guys screw that up when they build Kaalia. I think if you continue to work on it though, you should focus on the manabase first for sure. Heres my list if you want to take a look, and any suggestions you have are welcome. Kaalia Beatdown

Agreed on the mana base, guildgates are definitly not the best. I will change some stuff around

Added Dragon Tempest instead of Fervor

Removed Guildgates, Added double mana +1 life lands

Added Gravedigger seems good but I don't know any better options.

This deck could use a Master of Cruelties.

Added him to the sideboard, I'm also considering removing Iona, Shield of Emeria

I'd add one more land, add a Steelshaper's Gift and add a Subjugator Angel.

Steelshaper's Gift is very interesting and kinda better than Open the Armory.

Subjugator Angel is only good during one turn, doesn't quite win me the game. Perhaps I could swap it with Reya Dawnbringer

I kinda have to drop cards at the moment if I want to add cards.

Kaalia is all about those ETB effects, and tapping down all of your opponents blockers is really good.
I think you cut the Mimic Vat and the Hero's Blade. Mimic Vat doesn't really fit in well, and Hero's Blade isn't very powerful. Reya would be an okay cut.

I really like mimic vat , It can lock a game down by itself, if my opponents kill the Subjugator Angel, it can be back every turns.

But I'm okay with cutting Reya and Hero's blade

I'll add Subjugator Angel and Ancient Ziggurat

I'm a big fan of Cloudshift shenanigans. I really like that you were able to include this on your list.

Mardu decks need some help with card draw for the mid to late game. You could probably cut 2-3 creatures and add Promise of Power and Necropotence. If those are out of your price range then Read the Bones is a good alternative. You should also add some of black's amazing tutors, at the very least Diabolic Tutor, or Demonic Tutor.

Also consider adding Bogardan Hellkite for its ETB.

Yea Cloudshift is a super fun card

I added Promise of Power and Read the Bones and Diabolic Tutor

Not sure about Bogardan Hellkite , but if I can fit him, I will

Necropotence and Demonic Tutor would be nice but I'm keeping a little budget.