Possibly uncalled for, but here are some design ideas I can spitball based on what you've done and the issues I've listed:
I think what would change the experience would be by making it vertical instead of having both axes. No point to being an archer when what I feel makes gameplay better is standing an inch away from the enemies (and that also adds the question that if I can move that up close, there ought to be a close range weapon and that's too much too concern oneself with.) Depending on how you'd organize it, you don't even need to worry about the walking animation, the player could be just the waist up character aiming the bow upwards. (If you cant picture what I mean I can draw it for clarity). Making it vertical covers why it needs to be done by an archer (enemies are airborne) and would also explain the arrows returning after a while (and then the arrows getting stuck on the enemy would also have a mechanical purpose: When you kill the enemy with arrows stuck on it, you get all your arrows back instantly, while arrows you miss are lost in the sky for a while until they fall back and you get them once again; this lets it be tactical as you want and punishes the player for not properly aiming. As for the baby ball question, I think what would be necessary is increasing the numbers for damage and HP, so that you can have your real proper elven arrows that deal X damage, and once you're out of them you're shooting inferior human arrows, which are infinite but deal less than X damage (and thus allows you to also generate upgrades and items that buff these human arrows so the player can do a no elven ammo build or something of the kind).
Next, you'd think "but if enemies are coming from above, can we still be doing orcs?" and this actually connects to my point about the items being cute in BBattles. Change the enemies to orcs that are parashooting or riding birds or balloons and all sorts of silly or cool things you can imagine, and that'll give the game some visual identity and personality + explain why these enemies are static and not countering you at all. They're trying to land, not walking slowly towards your home base, they're defenseless truly. If you want to take it a step further, you can make them kamikaze and when they land they explode and your base takes damage, their goal isn't even to invade, just suicide bomb on top of you.
And this is absolutely minor, but having a human geezer just standing there and trying to make a profit while you're fighting for your life doesn't feel right story-wise, so I'd suggest changing that guy into a goblin. He warned you about the incoming attack and he is trying to sell you goods to make a profit out of the conflict (and even if the invasion succeeds, he can say he was a captive; he wins no matter who comes out on top of this conflict, so all he cares about is the profit he can make.) A sprinkle of story and character without needing to say much goes a long way.