They say a season per book and there is a lot of talk about how it will be plenty of time, but then they may announce later that they'll be 4 episode seasons with 30 minute episodes.
Most likely what we will get is 10 one hour-long episodes a season like Game of Thrones did. They will still want to air these on HBO. Granted I don't know how you could fill ten episodes with the first book.
I wish they had EXTRA time. I would like to be able to explore some character stuff that didn't get covered in the books even. What does Voldemort want?
He wants to fill that void inside of him. Due to being conceived under a love potion and growing up from a baby in the orphanage, where he already was using his powers before Dumbledore showed up, he has a void inside of himself. I think JK Rowling liked the movie Tombstone because she stole this right from the film:
Wyatt Earp:
What makes a man like Ringo, Doc? What makes him do the things he does?
Doc Holliday:
A man like Ringo has got a great big hole, right in the middle of himself. And he can never kill enough, or steal enough, or inflict enough pain to ever fill it.
Wyatt Earp:
What does he want?
Doc Holliday:
Revenge.
Wyatt Earp:
For what?
Doc Holliday:
Bein' born.
I saw a meme the other day that said what he had in common with Grindelwald was wanting to take over the world, but I don't see the evidence.
He did take over the ministry, offered every dark creature an expanded place in the world under his rule, put anti-muggle wizards in charge of the ministry, and remade the statue to show wizards standing on top of muggles. After he thought Harry was dead, Voldermort was going to have Hogwarts all be Slytherin house. He also started attacking Muggles as soon as the end of Book 5 when the Mister finally saw him with his own eyes.
Certainly he put a puppet in charge of the Ministry of Magic, but I never heard about any grand plan. He doesn't seem interested in any of the trappings of authority. He doesn't care about money or fancy stuff. He walks around barefoot in Malfoy Manor. I really believe everything he did when he came back was about his own security and personal perfection. He wanted the Elder Wand and he needed Dumbledore and Harry Potter out of the picture and doesn't want auror's hunting him.
He definitely prioritizes what he wants and needs to do on his return.
1. He tries to get a complete copy of the prophecy so he can know the whole story instead of the first part that Snape had overheard.
2. He tries to gather Giants, werewolves, dementors, and imprisoned Death Eaters to his side.
3. After he is revealed, he tries to have Dumbledore killed, as he knows Dumbledore is not only better than him, but will be leading the resistence.
4. He kidnaps THE wand expert to find out why his wand and Harry's seem to have issues when dueling.
5. He takes over the ministry completely and starts purging muggle born wizards. (Remember Tom Riddle did the same thing in Hogwarts)
6. He reforms the curriculum at Hogwarts and uses Death Eaters for teachers and Snape for the head master.
7. Starts searching for the Elder Wand.
All that is pretty much a prioritization of protecting himself, but its understandable as he had like 13-14 years to plot and plan on his next step and doesn't want to go back to that condition.
I don't think he gives two flips about what the muggles do with their silly lives. I don't think he wants to be in charge of anything. He just doesn't want to be bothered.
He does though. He hates muggle-born wizards, he has that prejudiced we see in his diary self. Once he was back into the open, he started attacking muggles again directly. While he doesn't want to be minister of magic, he wants that minister to be his puppet. He never really gets to live his plans though, as the original Order of the Phoenix seems to stop him, then he gets blown up by his own spell, and we get the events of the books/films.