Flew LHR-DFW a couple of years ago and the entire 77W IFE/wifi was down. Was proactively given 10k miles or thereabouts by AA customer service. Flight wasn't too bad as everyone in the J cabin was passing around whatever we had with us, such as magazines and books so we could share.

I did write to AA CS after as well, not in search of additional comp, but to provide feedback on the process. The IFE was down in JFK before the aircraft even left for LHR and then spent many hours on the ground in LHR prior to our flight during which period AA did not tell us diddly-squat. We only found out after boarding. AA should have made announcements in the boarding area and lounge which would have allowed many of us to go stock up on a few extra books.