I would have thought the Board having direct input from the 'shop floor' as it were, would be a bonus in a large company, where normally they would have to rely on info 'trickling up' via middle management. Terminal 5 springs to mind, many on the ground had doubts about the opening which were not taken as seriously as it eventually proved they should have been further up the chain.
A direct route to the Board from the floor would keep middle management on it's toes.
I daresay there would have to be a confidentiality agreement as to what areas can be reported back on and what not, but not insurmountable if the will was there.
Interesting looking at Lufthansa's Board, there is a conventional 'Executive Board' plus the 'Supervisory Board' made up of shareholders and employee representatives.
This link is to the Lufthansa page detailing the areas of responsibility, which also makes it clear this is normal in German companies.