Also, imagine that nerd!Izuna was like Obito - more of a put-things-together-on-the-fly-even-though-they-should-never-work sort of person, and that's why Madara takes him under his wing. He's just like, "omg, he's just like Izuna," and "little brother is that you". And instead of hating Tobirama 'cause he killed Izuna, Madara hates him 'cause they kept teaming up and doing ridiculous things that defied the laws of the universe. Madara was jealous. But Tobi and Izuna were bros. Science bros.
I will accept this. This is good. Madara’s anger all came from the fact that Izuna called dibs before he could.