Cloning, and what that entails
- Okay, according to EU, Luke Skywalker got a clone named 'Luuke' who was cloned by using his severed arm, with the same cabilities in the force, could be trained to match him in lightsaber combat, and could have their mind completely controlled by a Dark Side-master. Now, my problem is, why didn't Palpatine clone Anakin Skywalker's cut off arm, severed during Attack of the Clones? It was severed in Dooku's Hanger, later investigated by the Republic, which Palpatine controlled, so if he wanted the arm he could have retrieved it, and then with his secret cloning facility using Spaarti cloning chambers on Centax-2, he could have a clone as powerful as Anakin (and more, because he is four-limbed and probably could best post-Attack of the Clones Anakin, and definitely best Darth Vader), but under his complete control. It would've saved a lot of coercement necessary with real Anakin, and a lot of other things.
- Because a Sith Apprentice is supposed to be a Bastard Understudy, with all that entails, not just a mindless slave- Palpatine's plan A was to live and rule forever, but if that failed, he still needed a right-hand-man capable of continuing a Sith-led Empire for him. As for why he didn't clone Anakin in addition to Vader- do you really think Vader would have stood for that, had he known?
- Force-growing a clone without it going insane requires using ysalamiri to insulate the developing clone from the force, and there's no evidence that Palpatine knew that they existed. Clones that are grown at only twice speed don't seem to have their original's memories.
- Pretty sure Thrawn implied the Emperor knew about the ysalamiri, but never used them for reasons that should be obvious. As for not having insane clones: Another way to do it is to have the clone grow naturally. It takes longer, but said clone then has, well, everything the original did, including access to the Force. Thrawn himself tried this in the Hand of Thrawn duology, having a clone of himself created should his mission in the Thrawn Trilogy fail. Then the clone got murdered while still in its cylinder by Luke and Mara.
- Retcon. Since the Trawn-trilogy is years older than The Phantom Menace, Zahn had no idea of the midichlorians, when he created the Luke clone. Midiclorians are obviously based on the Real Life organells mitochondria, and as such they much likely have their own DNA, which has no connection to the host's own DNA. This means that cloning a Jedi's DNA sample will create a perfect genetic replica, but it won't have anywhere near the original's amount of midiclorians, and thus would be completely Forceless, or at least vastly inferior.