They don't have to learn control, so much as learn to watch their backs. The Sith are all about absolute power, and knocking over/off anyone who stands in their way. That includes their own Masters.
That being the case, I was very unconvinced with Anakin having Dark Side tendencies. The excuse put forth by defenders of Lucas/Lloyd/Christensen is that the Dark Side can dominate absolutely everyone, and it's so easy to fall into it, yet, I remember something being said that Anakin had an inkling of evil in him, and that he was much more susceptible to the Dark Side's draw.
With Lloyd's performance and Christensen's Ep. 2 performance, I was not seeing it. I was not telling myself that this guy was definitely going to evolve into the evil bastard who killed so many Jedi and tortured the Rebels in the original trilogy. It wasn't until ep. 3 that I began to see the similarities, which is why Christensen was redeemed in my eyes. Nevertheless, it was still quite a drastic change from good to evil.