The title say it all
The sharingan is the uchiha blood line power This mean they born with the potential of getting the sharingan.

Sasuke
Sasuke is a born genius stated by many senior ninja in konoha and other villages.Sasuke without sharingan can still do all lightning release,fire release,good at weaponary,good at taijutsu etc.I believe sasuke will be like minato without sharingan.
MINATO
Minato was also a genius in combat.He was like naruto but with intellegent and more knowledge of jutsu.

Naruto
Naruto without sharingan will not be able to think through battle,very easy to be predictable or very vulnerable .He will not have also the ability to heal,used effect resengan variation and speed.
However Sage mode will be the only help for him but he will not have the speed dodge his oponent attacks.He will jutsu rely on Ma and Pa toad to think for him when they fuse.