To be honest this feels quite hard on BA/AA. The connection was tight, AA were late, and you were proactively reprotected. You didn't arrive at the gate until 8.50pm and the BA flight was due to depart from a different terminal at 9.30pm. OK, it was delayed 15 minutes, but was that delay known at the time the decision was made to offload you? And even if it was, is it practical that operational delays of this nature be factored in for compliance-type events such as this? And why comment about your bags not arriving, what did you expect?
On top of all this, you were given a 2 class upgrade to CW from Y for a long overnight flight. All credit for disclosing this yourself, but in context this seems quite harsh.