Now, you claim the attacks are not energy, which is bull. Also, assuming they are only "elemental", it means Kenpachi can evade them without moving. As noted in the earliest part of Bleach, entities such as Hollows, Shinigami and such are incorporeal unless choosing to maintain a material status, thus physical obstructions and the like don't affect them. Also why they can "run" on air and essentially fly in the Living World. Unless you can say the attacks are using Kyo's spiritual energy to create them, then as only Elements in the Physical world, they won't affect Kenpachi as a Shinigami.
Everything else is just power wanking. Kenpachi doesn't need it because he is, simply put, a ridiculous power house. His reiatsu aura pierces the atmosphere and Hollows larger than buildings are killed effortlessly with single blows. As for Ichigo, if it wasn't obvious it was hypersonic, then you weren't paying attention. Byakuya proved very early that even at a fraction of his power he was super-sonic. Senbonzakura is at least as fast as he is, as the petals have less resistance against them. Also that was Seireitei Arc and a number of Cast members were upgraded for Hueco Mundo arc. Also, take the Name of Techniques with a bag of salt. Remember, Shunpo, aka Flash Step, translates to "Light Step" and can be interpreted as stepping at the speed of light. And we have Yoruichi who has been called the "Goddess of Flash" due to her speed and mastery of Shunpo. Does this actually mean it's a lightspeed move? No. Does Sonido, which translates to Sound, move at sound speed? No. It's much faster than that, obviously given both the Speeds already shown. It's just a name.
Im not going to argue with you on that lightning buisness, mainly because I have no intrest in it but mostly because my input wont change a thing anyway in regards to it.
But other things you have stated about bleach are untrue.
1. Shunpo litterly translates to "Lightning Step" not "Light Step" hence where they got "Flash Step" from, because the users movements seem to be done in a flash, its not because they move at the speed of light meerly because their movements seem to be just a flash to on-lookers. Masters of this style are Hypersonic and upwards, and Kenpachi does not have the skill of one of these masters, yes he did keep up with Byakuya but he was not using Flash Step to the fullest at the time. Which puts Kenpachi's speed at an Expert level of the Style at best if he could use it. Which puts his speed up into the high supersonic category. He has never proved that he can go faster than that so claiming he can is pointless unless you have something to back it up with.
2. While the Soul Reapers and Hollows/Arrancar are non-coporeal (With them being souls or spirits) this does not give them the powers of Intangibility (Unable to be affected by physical forces such as walls and telephone poles). The only showning of them passing through a physical object without injury is at the start of the series when Rukia goes through Ichigo's wall. This was clearly just for plot conveinince (Mainly to scare ichigo into beleving that he was talking to a Soul Reaper) after a few chapters when Chad managed to hit a hollow with a telephone pole. (The only exception to this the the Souls that are trapped in the human world, but because they are neither Soul Reaper or Hollow it wont matter too much)
3. They explained the reason they can walk on air after the soul society arc I believe. It is because they can solidify their Reiatsu beneath their feet so that can stand on thin air or in a place with no solid objects. Very Similar to Naruto's ability to walk on water.
4. As far as Kenpachi is concerned, He is only as strong as his strongest showing. Which I am afraid to say are much less than that of Kyo. I have no doubts that he is a very powerful character, and I agree with you that he need to be explored more in the main story so we can see the full extent of his power. But as of right now he is only as strong as his strongest showing, and claiming he is anything above that may prove to be untrue or false later on.
So im going with Kyo due to his insanely greater speed and skills