This is roughly the norm now. At least 40 minutes I find. Sometimes you might be lucky and they come out quickly (I once walked from the plane), straight through security, to find my bag was coming out on the carousel. 15 mins from plane to bag. Other times, it's taken 1.5 hours.

I don't think this is all BA's direct fault though. Moving to another airline won't suddenly offer you a vastly improved service, through Heathrow. I've flown AA a few times recently and it's been shockingly poor - made flying CE through BA a pleasure.