On the BM load factors, there's the ever present asterisk of "good load factors can disguise awful yields".
I think that might partly explain HAM's apparent plateau. I rather suspect that route's demand is somewhat more intrinsically inelastic than the others, so yield is easy to obtain despite lower load factors. It certainly appears to be the case looking at lowest available fares on that route across a selection of dates.
FRA and MUC are the ones that need volume, IMHO. They either need to be cost-effective feed-throughs into the broader LH/*A network, or protect themselves against EZY (or even worse, FR) jumping in where they sniff an opportunity.
I met someone recently who had a choice between FR and BM from MIL. They took the time to compare cost and benefits, and plumped for BM from MXP, and were very impressed. Let's hope more people are getting similarly cannier about their flight purchasing.