umm 1st of all not all of the uchihas are fast....and there sharingan deosnt have anything to do with there speedhe would not need million years and its not stupid , madara is already fast without any ninjutsu, btw he will not put on every tree his seals just on important spots, the thing is he copyed minatos technique and he just improved and doing it on better way plus EMS helps him to use it more often and faster...
kakashi sharingan is slow very slow to uchihas sharingan cuz it cant keep up and resist MS too much....
2nd the sharingan or the MS/EMS cant copy all jutsus if they were able to copy all jutsus(like minato's jutsus) they would be invincible ...
3rd kakashi's sharingan isnt as slow as u think after all did u see when both naruto and kakshi were fighting itachi he wasnt affected by his genjutsu
he wasnt able to resist the MS before cuz he only had his normal sharingan at that time....