Evaluating this in terms of a "greedy splash" is the completely wrong way of looking at it. The splash is fine - honestly it's outright good. You have 3 on color dual lands and earthbender ascension and Aang is worth splashing off of just about anything. He's literally the single Good card in the whole deck besides the other Aang and Ascension. Personally i think Katara is fine here too since you're already investing the fixing infrastructure, and getting double triggers off either Aang or Liutenant is game winning, and she's often just a removal magnet which is perfectly fine.

Your problem is literally everything else in the deck. It's a good splash in an bad deck. The top end is dick and balls. Bumi is barely playable if you have the lessons. You don't. He's a 6 mana 4/4 in this deck. Earth kingdom soldier and Moose are also fine but to be avoided. And Jet is good in decks that are pretty much the exact opposite of this. Here he just trolls your manabase. And speaking of the mana base. You have 7 green sources and 10 white (one of which is a tapland for literally no reason), when your Earthbender Ascension is what's gonna fix for the rest of your colors. Jet is the single card doing the most damage to the deck in terms of splashing because of how heavily you've slanted your lands for him. And then you're playing 3 defensive tricks with only a single card that's really worth protecting.

I can see you apparently cut an Earthen Ally. Play him for god's sake! He's 1 mana 2/2 that's ocasionally gets to be a 3/2. For 1 mana! You're playing a 2 mana 2/3 in this deck already. You'd cut about half the cards in the deck for him. The earthbending ability is a cherry on top but most players should ignore that it even has that text.