My theory on Bleach.
Aizen is Ichigo's long long lost son/grandchild/great grandchild from the future who happens to have went back into time because the Aizen we know now destroyed the Reiatsu train thingy.
THAT'S RIGHT, KUBO DELIBERATELY ALLOW TIME TRAVEL TO BE POSSIBLE IN BLEACH, SO ALL HELL HAS BROKEN LOOSE IN THIS MANGA. At this point Kubo can do whatever he wants and go in whatever direction he wants and it'll all make "sense."
Don't worry guys, we have until "Deicide 18" until all this filler crap is over with.