star wars - Why Did the Empire Use Storm/Clone Troopers and not Droids?

I cant provide sources, but this is more of an opinion, firstly, if the Emperor were to maintain complete control after the crisis was averted, he would need a common enemy for all of the (Old) republic to get behind, this would be the Droids, even with his special powers and knowledge of the dark side the emperor couldn't force an entire galaxy to follow him despite the fact he's using the droids they elected him to destroy to control them. Secondly is a complete theory, but given the humano-centric nature of the Empire, with a few very rare exceptions, notice that most of the droid-manufacturers are not human, the only exception (correct me if i'm wrong) being Dooku, who was the emperors apprentice anyway; perhaps he favoured the clones as being a way of establishing human dominance unquestionably (despite the clones being made by non-humans, no one knew this), when the droids would've represented an alien power. Yaknow, common enemy and suchlike. Having a vague knowledge of the species Sith, and the tension between the Sith and humans who learn the Dark Side, this would hold a personal goal for the emperor: proving that the humans are dominant, that he is not inferior to the "true sith" in any way, for he created an empire of humans, made by humans.

WARNING: this part of my argument is a stray... I'm just babbling now.

In a way, doesnt it seem peculiar that in the original three aliens are in the rebellion, whereas the empire is all human, yet in the second trilogy of prequels, both the senate has a high rate of alien life, and the separatists. It seems to me that I get a mixture of signals from this, firstly that the Emperor has tried to focus all the aliens of considerable power to the Separatist movement for extermination, so that when he takes utter control he can get rid of those less powerful but still with influence via the dissolution of the senate, and have an all-human regime without anybody catching on. Secondly it makes me think that the separatists were MEANT to be all-alien, and the desperate shots of aliens in the senate were trying to emphasize equality of an entire galaxy BEFORE the Empire was formed, while hoping not to take away from the idea that the separatists were "THE ALIENS!" XD okay my brain hurts.