its not. sasukes has better feats both offense and durability.
offense
-ps sword slash chopping down massive CTs gives him the best shown dc of all the ps
-ps chidori stalemating bijjudama from Rikudou avatar.
Defense
-Tanking the combined explosion of ps chidori and bijju dama which blew off the head of hashiramas statue.
Bijju ps is self explanatory.
kakashi showed nothing of the sort except decent speed. kamui shuriken is deadly no doubt seeing as it can warp away ps sized objects, but it can be countered by intercepting them with big enough projectiles or simply dodging. other than that offense wise it showed nothing, no dc feat, also no durability feat so its below sasukes without bijju.
this how it goes based on feats all around.
Sasukes Bijuu ps>>Sasukes Non bijuu ps>>kakashi>>Madara(Non Jin)
ohh and itachi doesnt have Ps. his soosano is the weakest.