I like this a lot. It has a lot of energy and passion, as well as a lot of interesting creative choices to give the track originality. The only issue i had with it was that the low end (snare/drums mainly) did not have a ton of presence, and it seem a little out of balance. I feel this is a mix issue.

Am I the only one that thinks tuning a kick (apart from big room or trap kicks) is pointless? Like, I understand the reason, but for me keeping the kick tuneless makes it just a punch, rather than another melody in a way

No I very rarely, but do, run into this. There are times I am wondering... does this kick need to be in tune? The answer is usually no. Because the character of a kick drum is more important than exactly what frequency it lives at, from a sound perspective, not a mix perspective. Like you said when you tune a kick to the track it seems to gel with things harmonically and that is not always what you want. Usually you want it to be the foundation on which everything else exists... you chose the kick for how it sounds, and changing that for the benefit of the track's key will generally ruin the kick.

And snares, other drums are different though.

That being said, it's not ideal to have a kick that's so far out of key that it sounds flat or sharp. I think if you are playing withing 3 transpositions you are ok for some kicks. Some kicks will not tolerate even 1 transposition. Because, even though changing the kick to the tracks key may not be ideal, that doesn't mean the kick won't benefit from *some* transposition.

Granted, every case is completely different, this is just a rough response based on my experience. When I feel like i need to tune the kick, its usually because I am not getting the punch I want and I feel like maybe that had something to do with the key. It never has.

^ Agree with virtually all responses... and i will add depending on the genre you are making, what you decide to fill the empty space with may change. If i threw a dart at an EDM dartboard and it landed on progressive house, I might fill the space with pads, white noise, reverb tails, delay, etc... Trap maybe different... etc.

Also this might happen to me because I have nothing really powerful in the mids 600 down to 300 or so. This might be the lower octave of a synth chord or a lower voice on a melody. This is if it feels empty in its core guts. If it feels empty in the surround, or the air around it, then take a look at the reverb/delay of any stabs or pads you might have. Those tails can exist if you chain them a bit, even if the chaining isn't audible, it will allow them to exist in the track's mix without causing mud.

*P.S. Also, if you feel it is "missing something", not to be confused with "It feels empty", then it usually (in my personal experience) is the bottom end (sub to low bass OR a bass octave on your leads or stabs (which will be higher). Perhaps the bass and kick were not mixed first, or you have done something to the dynamics of the track that promote the mids and highs and washes out any bass, or you have phasing that is canceling the low end. Or, maybe you moved your room around and forgot to align your monitors and seat in the correct spots, and all that omnidirectional content is being canceled.

The three space related concepts that I am bumping around are:
1. "Feels Empty" - investigate pads, reverb/delay, stabs, octaves.
2. "Something is missing" - Investigate bottom end, consider adding vocals.
3. Emptiness as content: The use of emptiness in your art is a powerful device. But this is not a problem, but a tool.