It bothers me when people draw conclusions like "Anyone with Sharingan could learn any jutsu with no other effort required other than looking at the jutsu". That idea demeans the fact that all three of the people we've seen use the Sharingan were reputed as geniuses before they ever even activated their sharingans. Attributing everything they accomplished to Sharingan Shenanigans demeans their individual talent and cheapens their characters to Naruto levels.