As the title said. I was discussing with a friend this topic. I don´t think, that he will use his bankai. I guess his just testing his strength. I sure he will not use his full power in his shikai stage.
He won't use Bankai for now. Later on when he's against somebody that pushes him to the brink, then he shall. But as of now, Ichigo shall, as stated by you, test his strength.
No. Maybe if the 4 Sternritter go Vollstandig, that will be sufficient for the Bankai. Though I doubt 4 Vollstandig will push him that far, since he is annihilating one Vollstandig Sternritter while holding back in the Shikai.
why would he go bankai against these fodder? it's not like the old ichigo when he went bankai because the sun was shining, this is new and improved ichigo.
It is just a question, that I discussed with friends. I do not think he will release his bankai now. His bankai will be different. I think against Bach , he will use his hollow mask as well.