Why Tobi being Obito isn't a bad idea
I know this hasn't been completely confirmed but if it is in fact Obito's conciousness then it is actually a good idea, (plot holes aside of course*) although I would welcome it being just his body just as much, maybe even more.
*Just to defend Kishi, he hinted at Tobi being Obito long before the Minato and Kushina story and the fight with Konan, places most of the plot holes arise, he would know full well what inconsistencies have been created, I think this is much more complex than we know.
Anyway, there are three main reasons why Obito is a better candidate (Like I said holes in the time line aside
1. Obito's reveal would have the most effect on readers.
Obito is a character we know and have experienced, and was a liked character, was the best friend and rival of Kakashi, a fan favourite, this mirroring the Team 7 we all know and love. The other candidates like Kagami, or Izuna appeared in about five panels all together and we know nothing about them, their reveals were more wanted but, especially Kagami would have no effect on us as readers.
2. Gives Kishimoto a chance to develop a fan favourite.
Kakashi is one of the most popular characters in the series, and it was said by Kishimoto to be 'his year'. Through Tobi's reveal, we can find out more about Kakashi's mangekyo and his backround, how Rin died and Kakashi's role in making Obito the man he is today, also justifying the reason for Kakashi gaiden
3. Makes Tobi a more complex villain.
Obito being just like Naruto humanizes Tobi, and makes him more interesting, I personally want to find out what it possibly could be that changed him, that is why Shinobu Sensui of Yu Yu Hakusho is one of my favourite villains. The complexity to his character, the fact that he was such a pure young man who grew into a ruthless killer who wanted to exterminate humanity due to the horrors he had seen humans do. I explain the similarities here
The fact that he was like Naruto and saw things that turned him into who is suggest that anyone is corruptible due to the ninja system and justifies his desire to create a moons eye plan, his quote to crush ideals of shinobi seems to make sense now, we have seen this in many characters and hopefully this helps Naruto formulate his plan to bring peace (although he better not TNJ his way out of this one )