Surely that is just a reason to avoid LHR and not a certain type of aircraft? When I worked at LHR I would fly up and down to EDI regularly. Usually I had no checked in bagggage, but now and again I did. After 4 flights in a row with a bag (all on the last flight of the day which was an A321) where it had taken 70-90 minutes to get my bag I decided I'd no longer travel with a bag. I don't avoid A321s.
For the record, my A380 experiences have all been fine, but then I have always used them at airports where A380 suitable gates were in use (HKG, PEK, DXB, LHR, CDG) and never had to offload using stairs or single jetties.