I'll write a tutorial for dynamic lights and decals if Blitz3D gets more than two texture coord sets.

The idea of having more layers is making it less heavy to run and make use of the latest hardware which doesn't mind dealing with dense multitexturing.

It's far from something we absolutely need though, since we can already pull it off by multipass rendering or as sswift says, getting an extra surface instead.

There's plenty of smaller things that could have a greater impact on blitz's abilities.