well, has anybody thought of how madara's reaction would be if he sees th 4 hokage's coming to join the battelfield espicially the first hokage hashirama
He'd actually start trying, and we'll finally see what he is capable of. I mean, it's manga fact that as soon as he lost interest in fighting the Gokage, they were one-shotted.
I suspect that he has an ace up his sleave incase something like this actually happened. It would be a cop out if the Hokages stop Madara Uchiha, that would be easy and a boring way for him to go, especially sense he has just sort of been standing to the side throughout the current battle.
Plus Tobirama said that they are not at full strength.
Let's face it, we have yet to see Madara's full power as he was only playing around with the Kages, and when they out-lived their excitement, he flattened them in one go. Plus, we have also not seen that hidden EMS Tech from him or Sasuke. He will most probably pull it out against Hashirama. The fight will get intense.