Does different wavelengths of light create different results. If you have too much blue light during flowering would it create a leafy plant? Would you want more red? Possibly more blue during stretch then dim it a bit. More red then blue at the end. I don't know.

You guys are right. If I owned a LED with a dimmer I would most likely just crank both up during flowering. There are people that use MH for flower?
The point of the dimmer would be to use different wavelength ratios depending what stage of growth you are in. The same reason people use a different light for veg and then one for flower.
Has anyone done a side by side with an MH and HPS for flower? Does the MH create more leafy growth?
This would be a reason for a dimmer.
If this reason exists. I have no idea.
I have heard people claim to much LED during flowering is not good? (I do not know if I believe that) but if it is true it is another reason to crank up a more beneficial wavelength and mellow out another. Kind of like what you do with nutrients.
These are some reasons a dimmer would be nice. If these reasons even exist. There could be more???? Or maybe a dimmer is an unnecessary idea...