Needs to be a reason to fly multiple bombers, other than for mutual gun-assistance. Flattening fields is generally cussed at and frowned upon. So what would you want multiple lancasters for?
There needs to be some way for players to undo field-aquiring damage more speedily. People are very unkeen on bombers doing the full thing of flatten-factories, flatten field, C47 at your leisure, because after you take the field it'll be out of commission for way too long.
K