I see that a LOT of u are completely missing the point of what Sharingan is.
Look Sharingan is basically a special eye technique. a Doujutsu.
Sharingan is made for battle. This is where it excels as an aid for battle to enhance the user's abilities further. Not all Uchiha's are the same nor have the same abilities with Sharingan. The same as how not all Hyuuga are the same nor have the same abilities with Byakugan.
However Byakugan is mostly a scouting technique. but depending on the user and how it's used it can be a very powerful weapon.
Sharingan specially is a great enhancement to the user. All Uchiha clan members are differently they arent clones of each other, they dont all develop sharingan at the same time (or at all), they have different traits and aptitudes. For example ANYONE can learn to drive a car, but NOT everyone can be a pro race car driver. Just having a car doesnt make u a pro driver, and even then, having a car doesnt mean that your car is the same as everyone elses. Sure they have many similarities but all cars are different.
As such we can see with Sharingan. All sharingan have similarities it's main effect seems to be to abe able to see chakra and to super analyze things. This is what allows for the "copy" skills.
Kakashi was the "Copy Ninja" before he attained his Sharingan. What do i have to base this on? Well in the Kakashi Gaiden he was already at Jounin level and he had JUST developed Chidori. Which is his ONLY original move. Kakashi is a genius, it's his own unique talent to be able to copy and master other jutsus. The Sharingan simply enhanced his abilities. Kakashi's talent is in Ninjutsu which we can see in the databook as he has this stat MAXED out, as well as performing seals. These are his strong points. Sharingan can be used to enhance ninjutsu skills by allowing you to see the seals and what not clearly.
Itachi as we seen has talent in Genjutsu. This is his strong point and his sharingan has been made to enhance his genjutsu skills even further. Thats why he has the crazy genjutsu while u dont see him performing many other skills that require his sharingan. otehr than the black flame.
Sasuke has talent in ninjutsu AND taijutsu. However sasuke's talents have been in many areas he's a true "all round" power house and this is why i believe that Tobi said "Sasuke has showed proper use of hte sharingan" because most likely the sharingan is not made the most of by using it as an enhance ment for just ninjutsu or genjutsu. It's most likely meant to boast all your skills notice how Sasuke truly does use his Sharingan to max efficiency. Compared to kakashi or itachi who are the only 2 who we've seen using sharingan in fights other than Sasuke.
Sasuke increases his reflexes, his intelligence, his ninjutus, taijutsu and genjutsu all together when using his Sharingan. but this is something that only Sasuke has talent in, and thus could have the potential to surpass Itachi once his base skills increase.