im wondering if ichigo would be different to the vaizards as he got both hollow and shinigami powers when he was created, while the vaizards were shinigamis who gained hollow power

aizen in himself is extremely strong and id say he could take on the menos, but also hes creating an army for them, they made a deal which they both like the final result, an army of harmen with aizen as their creator ruling them, if the menos are stronger then the hamen (which i doubt) then they might act as the generals or something