Each of you brings an interesting point so let me address them together .
If you note it has been stated that one eye of the MS specializes in Genjutsu while the other is in Ninjutsu. However when it comes to transplants things may change up a bit so lets take a look at those with one eye transplants
Kakashi = Sharingan in the left eye
Danzou = Sharingan in the right eye
Tobi = Sharingan in the right eye
Notice that those that have right eye transplants use the Genjutsu abilities of the Sharingan so perhaps which eye socket replaced will determine which side of the Nin/Gen side their power lays. However there may be more to it than that as well so lets go into detail here:
- Kakashi uses Kamui a time space jutsu that allows him to teleport at a distance but very similar to Tobi and the one thing they both share in common is they both have transplanted eyes and have obtained MS. One might wonder why doesnt Kakashi use Amatersu then but it may relate to the fact that Kakashi as far as the manga is concerned is not a Fire type like most Uchiha are. He has only used Lightning, Water & Earth so if using Amatersu requires one to have Fire affinity that would explain that angle.
- Danzou as far as we know may not have MS but may be using Shisui's hypnosis ability of his basic Sharingan. However to be fair it could easily be implied given the new information Itachi gave us that Danzou did in fact use the Shisui's MS Kotoamatsukami given he also has Shodais arm. This is still a bit unclear but perhaps will be explained later.
- Tobi does not have just MS but EMS and as Itachi stated transplanting the MS eyes also grants a 3rd new power. In any case Tobi we know uses the Genjutsu abilities of his EMS not Amatersu. However he also uses the time space jutsu which is like opposite of Kakashi allowing him to teleport only at close range unlike Kakashi who can teleport at long range. This fact may be because hes using the eye that is weaker in Ninjutsu yet strong in Genjutsu so it limits his time space range. In any case I think the 3rd power is this time space jutsu Kakashi & Tobi use.
- Sasuke who has recently transplanted Itachi's eyes and gained EMS may clear up the Time space jutsu theory of mine.