Very insightful post my friend. I agree with you, that the basis for the Sharingan's abilities is added perception. But beyond the Tomoe'd Sharingan, the Sharingan transcends in to a whole different type of monster capable of different capabilities. I understand the OPness (Not even a word....) of "Yomi" but when your rival is paralleled to the strongest to ever live (Rikudou), hax is needed to alleviate it.Hmm... the recollection of data is from the highest quality, and the conclusions you have do have indeed a deep level of insight.
All what you said as theory (not the data collection, since that's pure fact) is really possible. But what really makes me feel worried is the probability of Sasuke awakening "Yomi" (Time Manipulation).
The technique is quite OP, but more important, it goes against a highly primordial principle stated in the manga... it was stated by Lee in his first fight with Sasuke.
Do you remember that he said that even if Sasuke was able to see his moves, his body wouldn't be able to react since Sasuke's body wasn't trained to keep that speed? There relies the problem. When a Taijutsu user forces his body to travel great distances in a burst their body muscles would suffer damage due the pressure implied in traveling in that fast rate.
The same applies in Yomi, since being able to slowdown time would imply (based on the theory of relativity) that every non-affected object/person traveling in the affected volume would suffer the effects of pressure (for example, if Sasuke uses Yomi inside a battle and he uses shunshin inside the Yomi field, his muscles would be destroyed in the process since the technique affects time but not space, nor density. It would be like throwing a debris into the atmosphere, it would burn to crisp before reaching the sea or the earth.
---
PS: I have to admit, the technique didn't just sound OP at first, but it sounded impossible, since the idea behind the Sharingan is limited to perception. The sharingan let its user to have a better perception of reality, and in the case of Tsukiyomi, it affects the perception of the target, creating the illusion of the time-stretching "only and only in the target", and in the user in order to have control over the genjutsu.
It gained a little sense when I thought about the Kamui technique, but even so I don't feel so convinced, since Kamui is not a Space-Time technique. It is related to inter-dimensional traveling, and that is related to another different dimension.
Obito is capable to "retrieve and hold" anything inside the kamui, and "put this out of the kamui" in a late time. That is not space-time manipulation, that is a inter-dimensional vortex, totally parallel to the reality. If we speak technically about teleportation, or a "wormhole vortex", that would be like Minato's technique that opens a gate and instantly brings the transported object into another place of reality. So about the Sharingan, there is not technically any technique capable to manipulate time... there are only techniques able to manipulate perception of time on the desired targets.
Anyways, as I have an open mind and I gave space for doubts, I still think this technique is plausible, BUT given the characteristics of this technique, I have to put some emphasis and declare that it should have the same characteristics as Kotoamatsukami... yes, the eye shouldn't be able to function after the use of such extreme technique during some time, or in the best of cases, the amount of chakra needed for this jutsu have to be ridiculously high.
Think of it like Sasuke's version of an overpowered Izanagi that only he can utilize.