Proposition: Kamui (technique) becomes a 'formal' MS-technique, and any speculated relation(s) it has to Jikuukan Ido should be disregarded until the manga proves otherwise, of which I believe should also become a 'formal' MS-technique (although usage of it may be negotiated by both the user and the party/ies to engage in RP involving well, it).
My Reason: Too many times have I seen MS-possessing character claim Kamui (technique) as an un-slotted MS-technique, and can hence be used as a second (in the case of a single-eye implant), three (in the case where a fusion hasn't been claimed (i.e. Susanoo; unlikely case) or fourth MS-related technique. Many appear to be claiming it because on Narutopedia it is stated that "If one spends a lot of time and trains one's chakra over and over again, this technique can be invoked", although relatively similar circumstances apply to both Hachimon and Sage Mode, of which already possess resets on-site. The fact that there are practically no restrictions being applied to the claiming of Kamui (technique) saved for Narutopedia's reasoning literally led to 10+ people claiming it with little to no repercussions to the quantity of MS-derived techniques already in their possession. Now, if we're well and truly claiming that "If one spends a lot of time and trains one's chakra over and over again, this technique can be invoked", then why even bother requiring a MS in the first place, it isn't mentioned there at all!
All I'm really after is a prevention to the abuse of this detrimentally-convenient technique, is all right now.