I know exactly the feeling!
Flying from DUS myself quite a lot these days: a little bit more miles, but exactly the same time loss, with the added benefit that it's much cheaper too (tickets as well as car park).
Looking at how people at my work fly, BRU seems to attract its customers predominantly from just the north and west of our country as they don't have a good alternative: everybody in the east has several good alternatives right across the Belgian border while I think much of the (leisure) market in the south is scooped empty by the airlines flying from CRL?
What does this say about BRU: it's the airport of choice of nobody in Belgium?!?
Time to do something about it I'd say and no, people aren't waiting for even more shops!
New and cheaper car parks, smooth public transport access from downtown Brussels and other cities in Belgium, faster ground processes and much lower user fees and taxes are urgently needed to turn BRU from a very high yielding equity investment for its institutional shareholders into a customer oriented user friendly airport again.
( sorry for gong off topic )