Chidori>RaikiriRaikiri > Chidori
They're 2 different things, my good man.
feats wise
i will cancell out all attacks according to databooks.The Yata mirror reflects attacks in the manner you speak; however, it cannot likely reflect space and time.
Kamui is A dimension that literally exists in one individual's mind/eye (Obito). It's pretty much impossible for it to copy something that doesn't naturally exist... As Kamui opens a rift to a dimension in which the Yata doesn't exist. If it had transformed into Kamui, it theoretically would be sent into Kamui as it has used Kamui on itself. Having blocked the attack, it cannot re-register Kamui, and thus it would be lost in Kamuiland.
This also presents the fault of the mirror. It blocks attacks by reflecting them. As such, simultaneous strikes by different elements would in effect breach it due to the fact a mirror would be reflecting the first attack to hit it... The second attack not being blocked for the mirror reflects the first attack that's in the way.
Naturally Susanoo itself holds a strong defense, but combine strong enough attacks and one could overcome the Yata and Susanoo in this manner.
A second weakness would simply be to disable the Susanoo... Which was needed for it to appear. Things like Kabuto's Sound genjutsu would thus cancel it