These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Fridge Logic: Two of the filler arcs that Ichigo brings back memories of are stated at the beginning of their respective storylines to take place after the point at which he and Aizen would have gone back in time (the Shuuske Amagai arc and the Zanpakuto Rebellion arc). Therefore, Ichigo should have no memory of those events.
God-Mode Sue: Noted and justified; he's going after AIZEN after all. And even then, it's not his power that saved him but Muramasa's refusal to pick another wielder.