I've found that beating Kamino on hard with the Republic requires being on droideka patrol nearly all the time. You're right about clone stupidity on this level - They do seem to walk right into them.
Like you, I take four command posts as quickly as humanly possible. But generally, I try to avoid the cloning facility. First, since it is home base, it takes a while to convert and capture it. Secondly, it requires a lot of soldiers spread out over a big distance in order to hold it. I choose to give these two disadvantages to the Droid army. And they will pour a lot of troops towards taking it. Let their effort be in waste, and reposition your army to flank them on the platforms.
Holding four landing platforms is much easier. You can reduce enemy attacks to three essential chokepoints if you do this right. As long as you keep an eye open for droidekas, you will be in a dominant position.