From your intitial description of catching a lot of 12" LMB, that would be a tell-tale sign of bass overcrowding and most likely a lack of forage base.
It's been discussed a good bit on the forum, so I'm just summarizing without a lot of detail (as well as guessing on your situation).
If you do an electrofishing survey (safely, or with a pro), you might just want to be removing as many LBM under a certain size limit, as well as any other fish that won't contribute to trophy LMB.
Have you bought Lusk's book, Raising Trophy Bass?
