"Shen's Floating Sword doesn't fit his theme" well, Riot, what about this simple solution?

Make Shen and his sword switch roles.

TL;DR: The sword would move around Shen in a wide radius and shen could teledash to his sword, providing him with the same buff/debuff he has when his sword teledashes to him on live.

Shen's sword should move about him in a radius of length similar to Illaoi's and refresh its position on a timer similar to Fiora's, randomly cycling through nine or so different angles in relation to Shen(historically, nine was a significant number to many ninja).

There should be a decay timer both teams can see, but Shen should have a directional arrow or a placement marker appear in the last few seconds that shows the Shen player the general direction of the next spawn.

When Shen uses Q, he will teledash to his sword's position, which could exist anywhere in this radius on a cycle. If he passes through or lands on the enemy on the way to his sword, he procs the buff/debuff he has on live. This would promote good positioning from Shen and his lane opponent around Shen's relation to the sword, this also gives the sword something to do on-screen naturally instead of just existing one or two screens away until Shen is ready to fight.

If Shen's sword was behind him, he could use it as an escape. If it is behind the enemy, he could use it as an engage. If it is next to the fight, he could reposition and hit them from a better angle, if it is in brush he could teleport into hiding to catch his breath for a second(where did the ninja go?) In teamfights, he could use it to Insec into the enemy team and taunt one or two enemies back toward his team. Plenty of times an impatient or unaware Shen would be on his way out of a fight and press Q at the wrong time and end up back in the clutches of the enemy jungler and his laner. Or he'll engage and press Q when his sword is unfavorably placed and leave his team with the task of either cleaning up his mess with him arriving late or disengaging before the enemy realizes what happened.

Shen wouldn't get to choose where his sword landed, he would just choose when he goes to his sword.

He has E as a reliable less powerful engage/escape tool. He would have Q as an opportunistic one.

I feel this would be more complementary to his theme because:

1. Instead of Shen planting his spirit sword in the ground because he doesn't want to carry it in a sheath(Is it really that heavy?) he would actually use the bond of his spirit with the sword in combat to rematerialize from the sword and devastate his enemy.
2. Anyone can dash straight into their enemy, his identity as a ninja would be a lot more clear through the deceptive ways he could implement this skill.
3. His skill theme would be much more in line with Zed's, with clear distinction as to how opposite they are. (Zed manipulates shadows to do his bidding, Shen commits himself to his every action - the sword does nothing without the will of its master.)
4. Shen's story mentions often his ability to teleport almost at will. It seems only logical it should be central to his kit.
5. The majority of champs usually have at least one skill that is related or similar to their ultimate in some regard, whereas Shen is sorely lacking. This would make him more consistent with how most champs feel as well.

For reference, fighting the Grandmaster of the Kinkou would feel like when Raizo fought his former master in Ninja Assassin. DISCLAIMER: Gore, violence, blood, spoilers.

Or more or less Hanzo's final battle with Yukimura in Samurai Warriors where you know the attack could come from any direction, you just don't know when or where.

One other suggestion to possibly add to this concept would be to place the next sword's spawn placement around Shen's target instead of around Shen's position if you manage to land Q and hit them with all three buffed attacks for sticking power. (Thematically, cutting an enemy with the spirit sword would leave its essence in the wound).

Thank you for taking the time to look at my idea and I hope in the very least that you get some good ideas from it.

-Seiryuten