Sanderxpander
Craig, I understand what you're doing here but while that will limit individual bands perfectly, every individual band doesn't know what's happening in the other bands and none of them see the "total picture" which I think is the idea behind the L-series. Your mid band peak might be offset by your sub band dip for instance. Hope you understand what I'm getting at.
Yes, according to a review of the L3 in Sound on Sound, "The clever part of the design lies in the relationship between the peak detection and the attenuation. Conventional multi-band limiters split the signal into separate frequency bands and then limit each band independently. Here, however, the level in all five frequency bands is summed using a patent-pending algorithm Waves call the Peak Limiting Mixer. If, at a given instant, this sum exceeds the Threshold value,
L3 works out the amount of attenuation that is needed and intelligently distributes it across the different frequency bands. By default, the bands that are attenuated the most are those that contain the most energy, but it's also possible to instruct
L3 to concentrate the gain reduction in frequency bands where you think it will be less noticeable. The result, at least in theory, is that you can apply more overall limiting with fewer audible consequences."
It's true that a conventional multiband limiter does not do exactly the same thing. However if you don't apply much limiting, being able to "apply more overall limiting with fewer audible consequences" may or may not matter to you.