Generally, the demise of BM brings up the question of connections into Germany from BRS.
LH operated a flight to Frankfurt from 2008 to 2009,
puling it suddenly in the May after apparently taking fright at the unfolding financial crisis. I believe the anecdotal evidence was that the route was growing in advance of expectations. Ironically, I wrote a number of times to bmi (as was) during 2010-2012 to encourage them to consider BRS-Germany routes, given their relationship with LH at the time.
The existing BRS-SXF route that Easy operate is a primarily a leisure route. It's got erratic timings, there are no connection possibilities (because Easy don't do that, and SXF doesn't have any), and Berlin itself is not a major business or aviation centre in Germany. Similarly FR to CGN. But both those "low fare" routes support about 125 passengers per flight.
I can't believe that BRS can't support a well-considered route network to Germany. Whenever I travelled on BRS-FRA/MUC (which was often), load factors were in the 60-70%, and fares were in the £100s. I certainly know I paid noticeable premiums to start long-haul trips on LH from BRS using BM. When I travelled on HAM or DUS, loads were much lighter. (CAA stats bear this out - HAM and DUS each had a dreadful ~1,000 passengers in a month).
I think the BRU route is insightful. When SN operated it using an RJ, it used to be so full I could pretty much guarantee on an IDB offer (and compo) on the night flight from BRU-BRS. (KL fill 190s four or five times a day to AMS). After the introduction of the ERJs onto the route, capacity halved, fares shot up.
So I wonder if the problem with BM wasn't just the routes, but the aircraft AND the routes. ERJs are expensive per seat to run, so using them on places like MUC and FRA creates high fares. (Like, £600 return high). Using them on places like HAM and DUS seems very dangerous. And then there were all the complicated arrangements to maintain the MUC base, with its selection of curious routes (which no doubt LH were involved with selecting and underwriting).
Maybe BM needed to not own (or try to use) quite so many ERJs on thin routes in Europe. Maybe a different approach would have been a larger aircraft flying more consistently to a hub (which seems to be what SN have concluded, shifting the BRU route back to them and an Avro).
LH seem to be warming a bit more to the idea of regional flights feeding into the FRA/MUC hubs. Maybe it's time to re-approach them and put the case that a BRS-FRA/MUC route is sustainable if linked into the LH/*A network, operated with a bigger aircraft (CRJ900?) and with lower fares?
If not, maybe we can club together to lease two aircraft (not the bmi Embys!) and do it ourselves? Passenger power and all that.