No matter what, it doesn't change the fact that he was able to fight both on them in his condition...
That is so wrong.. How can you even count that fight ? Don't you realize that if that fight would take place now, after what Madara showed us, told us and stuff Hiruzen would get 1 shot with either Wood Dragon or Flower Tree World.
Some facts that completely denies that statement of Hiruzen vs Oro, Tobirama and Hashira.
1. At first lets recap of what they've done in that fight ( Hashirama and Tobirama ).
Hashirama - 1 Wood Style Jutsu that is much weaker than of Madaras.
Tobirama - 1 Water Jutsu which is weaker than Meis.
2. And now how about we think what they can do ?
Hashirama - Wood Dragon which is superior to Kyuubi, Flower Tree World which amazed all 5 Kages and almost killed them, Mokuton Jukai Koutan which took tons or even all of Kyuubis chakra and houndreds of Odama Rasengans to stop, just to stop it, Hashirama is known as the man who can heal his wounds without seals - the best healing Jutsu, Hashirama inheritates the power of Senju clan, the Body and Life Force, Wood Clones theyre very powerul, so that only Madara can see trough them plus those clones almost killed 5 Kages. There's Hashiramas secret scroll which contains tons of forbidden/s rank jutsus, also other mokuton jutsus by Hashirama, plus his battle experience and knowledge.
Tobirama - Space Time Ninjutsu, Edo Tensei, he can create Tsunamies in the place where is no water ( The strongest Water style ), also he has knowledge and battle experience.
So in overall recap Previous Hokages when summoned where at maximum of Jounin level, you can't take that fight into debate, that was long time ago, power levels were different, plot was different, everything was different and Kishimoto changed his mind, Hashirama is strongest Hokage, strongest Shinobi.