The new BHX expansion is very odd indeed. They must have extremely short memories of BHX-PMI and BHX-ALC, given that they flew these a few years ago, got run out of town very quickly and pulled off. All I can assume is that this is a cashflow generation exercise to get advance bookings in the bank, paid for up front.
And BHX-Cologne? Once a day, off peak? Surely the logical thing would be an extra frequency on BHX-Dusseldorf especially given that it's an existing route and the train services from DUS airport to Cologne are so good.
About the only one which makes sense is BHX-FLR - though it seems like rather high frequency.