Minato only compared Tobi to Madara because of the intel Tobi possessed not powerwise. Minato didn't know anything about Madara's power except that he was strong.
He compared Obito to Madara because of the ability he possessed.
He said that the only one who do walk through security, kill the thirds guard, extract the beast, and control it is Madara.
So yes, powerwise...
Unless you think an MS Tobi can do a better job than Madara with the 9 tails at getting Hashirama exhausted (they fought for a whole day) then even if Obito uses Izanagi immediately it won't make a difference because Hashirama can heal.
Madara's intent wasn't to kill, never stated he can do a better job...
But, MS Tobi is equal to Alive Blind Madara.....So yes.
Obito fought in the war for a day plus, he has Hashirama's cells so he has healing too.
Hashirama isn't healing from a hand being drive into his chest.
Rikudou Madara didn't so what makes you think Madara will?
He can absorb him too if I might add...
When Madara lost the fight he didn't even realize Hashi was a wood clone and he snuck up behind Madara and stabbed him.
Madara told the kages that he saw it, on top of that he wasn't fighting to kill.
You have to remember that...
Madara said "how did you get behind me." Hashirama didn't even want to kill Madara, but resolved to kill him at the end. If the intent is to kill, Hashirama will be even more hardcore. MS Tobi isn't on the same league as Hashirama.
Ya, then what did Madara say in response?
Madara lied, he told the kages that he saw it anyway.
Hashirama can't even touch Obito let alone kill him.
Seriously what can Hashirama do?
Obito took a raikiri to the heart, survived rinne tensei, and healed from a kcm rasengan to the arm.
Obito can shove his hand in his chest and start absorbing his chakra while intangible.
You're right, Obito is not on Hashirama's level...
He's way higher, he is on Blind Alive Madara's level.
He can summon Gedo mazou to dragon rip his soul (like he did when extracting the eight tails).
Six path Justus and yin yang technique too beat him too (chapter 606 page 15-16)