Just a little... clarification, from what I can gather about Vlad here.
Vlad III, was the son of Vlad II, Dracul, Dracul being his name because he was inducted into the Order of the Dragon, a Christian chivalric order, which at the time composed a number of nobles, almost all of which were opposed to the Ottoman Empire's expansion (hence the patronymic "Dracula", meaning "Son of the Dragon". Dracula has since that time come to mean "Son of the Devil", but this was not the connotation at the time, from what I can tell, and both Vlad II and Vlad III were reportedly quite pious, to some extent).
A little note about his name: Vlad wrote his name as "Wladislaus Dragwlya", which might mean he'd have gone by "Vladislav Dracula", but I'm not certain. "Tepes" is simply Romanian for "The Impaler", and he wasn't called this during his life, only after. However, the Turks did call him "Kazikli Bey" during his life, which means "Sir Impaler" or perhaps "Impaler Prince".
Despite his father's induction into the order, he felt the need to secure power in his country, which was constantly shifting rulers, and so Vlad II paid tribute to the sultan, and gave him his younger sons: Vlad III and Radu cel Frumos ("The Handsome") in order to secure the throne. Mircea II, Vlad II's oldest son, fought against the Ottomans openly with his father's knowledge, but without his support. He even captured a fort, but Vlad made more deals with the Ottomans and they basically got it back. The Hungarians started a campaign against the Ottomans but the battle was a failure. Mircea II and Vlad II (who had to at least look like he was siding with the Hungarians) blamed it on the commander, John Hunyadi.
Later on, boyars (nobles, basically) in league with Hunyadi attacked and killed Vlad II and Mircea II. It's said that Mircea II was blinded with iron stakes, and buried alive at Targoviste...
All this was going on while Vlad III and Radu were under the care of the Ottomans. Radu converted to Islam, and ingratiated himself to the sultan's son (and future sultan), Mehemed II, but by all reports Vlad III remained defiant, and was constantly punished for his insubordination.
(A quick footnote about Vlad's other half-brother, Vlad Calugarul ("The Monk"). He never really participated in the affairs described herein, and was rather pious. He did take the throne for a short while, but this was a while after the events of his brother's affairs.)
Despite this, when Vlad II (who remember, was backed by the Ottomans) was killed, the Ottomans marched to Wallachia and sat Vlad III on the throne as a proxy. This didn't last long before the Hungarians came in and put Vladislav II of the Danesti clan on the throne. Vlad III managed to flee to his uncle's in Moldovia, who was promptly assassinated, so Vlad III fled to Hungary, where he pleased the nobles with his extensive knowledge, and unyielding contempt for the Ottomans.
Mehmed II captured Constantinople, and Hunyadi (I think he was a regent, or governor, but I'm gonna call him "ruler" for now, despite the inaccuracy) launched a counterattack, while Vlad made his way back home, and reportedly defeated Vladislav II of Danesti. And this is finally where we get into the meat of his "reign of terror".
Wallachia was in an AWFUL state at this point, and whether or not you agree with stringent intimidation and harsh punishment for minor offenses, holy crap did it work. It's rumored that he placed a golden cup on a fountain in one town, knowing that nobody would steal it, and that nobody ever did. Vlad III eliminated most of the boyars, and replaced them with foreigners, or others who were inclined to be loyal solely to him. In lower positions, he preferred knights and free peasants. At one point, it's said that he gathered the homeless, poor, or other people he might have considered generally useless into a wood hut on the pretense of a feast, and then burned the building with them in it.
But he also strengthened the country's economy with new villages, farmland, and limited foreign traders to three towns, allowing local merchants more range, which built a stronger internal economy.
He blamed some Transylvanian Saxons about as much as he blamed the boyars for his country's problems, and raided their castles, impaling some nobles, and using the loot to pay his armies and mercenaries.
There was impaling, nailing turbans to people's heads, impaling, burning, impaling, SURPRISE ATTACK! Lots of guerrilla warfare, since Vlad spoke fluent Turkish and knew their customs and whatnot.
He killed thousands upon thousands of Turks (not all of them personally, though reports say he liked to be directly involved), and sometimes didn't bother counting the ones he burned or beheaded. Christians across Europe celebrated Vlad's massively successful campaigns. But eventually, Vlad had to withdraw to Moldovia, his brother Radu led a contingent of janissaries who were able to move in, and Vlad ran out of money, so he went to Matthias Corvinus, John Hunyadi's son. Who imprisoned him, on accusation of treason, because Matthias had spent all the money the Pope gave him to use in the war effort on hookers and blow (not literally, but seriously, up in smoke).
Look, I think you guys get it at this point. As far as the historical Vlad the Impaler goes, well... I don't see psychopathy or even sociopathy in his profile. I see a warlord, yes, but despite his insidious tactics, he was hardly considered worse than his adversaries, or many of the other famous warlords before him. He was a military intellect, a tactician, and the victim of a number of betrayals: his father's betrayal, his brother's betrayal, and the betrayal of a lot of allies.
I don't know about "tragic anti-hero", but he definitely wasn't a blatant monster. Not the historical Vlad Dracula. The one in the books even, is sort of more a "romantic villain".
Also, in the books, many of Dracula's abilities were learned from some academy of Satan in the Carpathians, where they taught black magic. In fact, it was presumed that this was the source of his shapeshifting, which also extended to a wolf, a cloud of mist, and a rat/pack of rats(?) (it's been a while). The vampirism itself doesn't seem to have anything to do with shapeshifting.
I'm... curious about this movie, but also very heavily invested in trying to learn more about the historical Vlad Dracula, so I feel like I'll grind my teeth at some of the inaccuracies, despite knowing that I can't expect them to do a documentary. I think I'll see it, but I don't know if I'll like it. Maybe I'll rent it or something.