[Hunter]

Originally Posted by Ero-Senn1n

For me it's the opposite, its actually interesting since they fight using their brain and not only some powerups. It's not that i don't like powerups, buti i like more outsmarting wins than overpowering wins since smart fights are rare. Too bad that the Itachi vs Kabuto fight, which involves two smart guys will most likely end in the next chapter. Maybe becuase if it lasted more then Sasuke would look kinda stupid, just standing there like an idiot

Pray tell, when did Itachi or Minato ever outsmarted anyone? They're too strong, they don't need to. Itachi uses Genjutsu and if it doesn't work he uses haxxed MS jutsu, if these don't work he apparently use Izanami yet another power up.
Same with Minato, he has one good jutsu that allows him to outspeed anyone and that's what he does. He throw his special kunai at the ennemy and when they are in position he teleports and strikes, the end. When has he ever used his teleporting power in a cunning way? He was never forced to resort to smart because he's too good, no need for Portal-like strategy when he beats everybody in 1 or 2 moves.
The need to outsmart the ennemy usually comes with the fact that you lack the firepower or the mean to get the job done. That's why Sasuke and Naruto had to outsmart Zabuza, why Shika had to outsmart Temari or why Sasuke had to find a way to reach Deidara for examples. But neither Itachi nor Minato ever needed that because they are way too powerful. They have always beaten their opponent because they had better jutsu.
It's particulary blatant here, Kabuto made sure he would be safe from Itachi's firepower (can't be killed) and Genjutsu (Sage-mode) so what happens? Itachi doesn't find a smart way to use his old technique despite the odds, he pulls out a new I-win jutsu out of thin air.

We have been told already that the rinnegan is the ultimate eye [...]

I will cut your paragraph here : we've seen the Juubi's eye as a mix of Sharingan and Rinnegan twice. There is more to it than you think.
Oh and as he showed Edo-Madara was never in any danger, he's just playing with them. I already had this discussion with someone else but the power they use will be driven by the plot, we have 4 doujutsu users fighting at the same time so they will each use different things to keep them distincts. EMS/MS for Sasuke and Itachi, Mokuton with very little bits of MS/Rinnegan for Madara and probably Rinnengan and space/time jutsu for Tobi.

I would hardly call those base if the user loses his eye after using them for just a brief period of time.

They doesn't require MS/EMS/Rinnegan so they are base Sharingan jutsu. They come with a huge price yes but base nonetheless. And indeed the EMS allowing them to be used at will (or perhaps with a cooldown since that would be invincible otherwise) would be a huge power-up but I doubt it will come to that.