Not on it own you need a complex bucket filler or glass bottle factory to harness the power of the mills. If the mills could take liquid water than I would agree but they don't.
The fact remains that it's still creating water out of... well, nothing.
Solar power takes in energy from the sun, and converts it into electricity. We already use this technology in the world, so it's not like this is science fiction. At night, it takes the same energy, simply reflected off the moon.
Yeah, solar power is powerful. However, nobody has given any reason to not like it aside from the fact that it's free energy.
But... my thermal generators, boilers, and normal generators all require the exact same amount of maintenance to operate: none. So, what exactly is the difference? Furthermore, how will making it a multiblock structure somehow mitigate the issue people have with it?