1. tobi fought minato as an adult just one year after obitos death. how did he get so tall and strong and how did he know kushinas seal would weaken?
2. kyuubi said "you..." upon feeling tobis intent/spotting his sharingan. kyuubi has never met obito nor felt evil intent from him. he recognises chakra easily like when he felt madara's. so wouldnt it come in handy for kyuubi to say "oi kakashi this here masked man is indentical to the chakra of your friend from 17 years ago"?
3. tobi said to kushina with cold unfamiliarity "do you know how LONG ive waited for this moment?" yeah 1 fukin year is a real long time obito...
4. minato, another skilled sensor and the smartest character in the series failed to recognise tobi as anyone besides uchiha madara since no other uchiha ever was capable of mastering kyuubi. and if madara trained a successor how, he wouldnt wait till he found a near dead crushed kid with 2 tomoes.
5. how would zetsu or madara or anyone know obitos body was under 2 tons of rock? WHY would they dig him out and rebuild him before he showed any special talent? do you know how many uchihas died in that war? more than just obito! and more suitable as a vessel/student since their bodies and eyes werent completely smashed.
6. theres a myth that tobi said to kakashi "you lived a life of regret" ohana whos fluent in jaapanese said tobi said "you DESERVE a life of regret"
7. zetsu is able to record events and battles. this is partly how tobi has such a knowledge about the shinobi world and posibly how he knew the seal would weaken during birth. unless tobi was in konoha during mito giving birth to tsunade's parent.
8. tobi said "your the third sage of six paths" to nagato. if madara lived to meet and train obito then that would mean he unlocked rinnegan AFTER nagato did. and it means that madara shouldnt be talking about nagato like nagatos a brat. since he wouldnt be even if madara didnt watch his progress over the years. brat = ******* way of referring to a young man. so the last time madara saw nagato he was young, and so was madara. since he died soon after getting rinnegan, and since tobi said madara's the second sage, that means madara died a long time before jiraiya ever met nagato and could never have met obito. debunking this theory and confirming kishis comment that tobi and madara know each other.
9. such a big twist would have to be foreshadowed earlier than now. like "madara" spending more time talking to kakashi than just in passing.
10. common arguments are that the name is similar. well so are danzo/hanzo, sasuke/sakura, A/bee. the list goes on. obito doesnt even translate to what tobi does.
11. the hair argument. tobis hair has changed often. it was long when he controlled mizukage/met itachi. which brings me to my next point
12. kakashi said 10 years before part 1 zabuza killed everyone as a child. "child" places zabuza around 12/13 since he talked about how his hands were stained with blood when he was narutos age. the blood mist practices came as a result of tobis reign of terror controlling yagura. i doubt mei would do this to her people. zabuza also attempted a coup de'at on the mizukage. zabuzas an ******* but hes not pure evil. he wouldnt try to overthrow mei. this means yagura reigned for at least 7 years. and two of those years were happening while obito was still an academy student in konoha. how did he move from konoha to kiri unseen and how did he hide such immense power/control mizukage from hundreds of miles away?
13. tobi has given claim to the fact he indirectly created akatsuki and indirectly awakened nagatos rinnegan. how could obito have done things occuring DECADES before his own birth? and why would madara have done this when as i pointed out nagato would damn well know if madara and tobi were different people based on the fact hes a chakra sensor.
14. similar abilities does not obito make. sasuke and itachi have susano. they arent the same person. jiraiya and kabuto have SM. they arent the same person.