Some airfields do a great job of mixing commercial and GA traffic. Some do a less good job and others do no job at all. There are three areas where the willingness of the airport management to make things work can be seen. Runway access and airside services, airside access and economic access.
Baden-Baden, Lubeck, La Rochelle, Dinard, Southend and Calvi are examples of those that score decent marks in all areas. Bournemouth and Exeter are examples of airports that fail on the airside access question - my last three visits have had different 'systems' - and places like Bristol, Luton, Farnborough and Edinburgh fail when it comes to economic access, i.e. they're bloody expensive.
I don't know exactly what motivates people to make things difficult (I can sort of see TAG's point of view at Farnborough where the movement are limited by planning permission), but there are plenty of shining beacons offering good examples should they have a change of heart.
Simple Pleasures : The Dawn Raid
5 months ago