I've just finished reading this rather good theory, written by one Joseph Tavano over at RetroZap.
I suggest reading it, as this is a direct response to that article.
I rather like his conclusion that Padmé's connection to the living force was being cut off, which ended her life. It fits really nicely, but his conclusion that Sidious was the one who did that is wrong on a few counts.
IV. "Have you ever heard of the tragedy of Darth Plagueis the Wise?"
Mr Tavano intimates that Sidious killed Plagueis only after learning all his secrets. However, after successfully turning Anakin to the dark side, before reappointing him darth vader, he says this:
To cheat death is a power only one has achieved, but if we work together, I know we can discover the secret.
He doesn't know it, he wants anakin's help to discover it. He isn't powerful enough alone. He NEEDS Darth Vader to achieve the power that his master had.
VI. “She was alive. I felt it.”
Yes, he did feel it. After he choked her, she was still alive, he felt it. Not during his reconstruction surgery, not when he woke up. He says this in past tense.
VII. There’s no other way Palpatine would know what’s happening to Padmé.
That's not true. Darth Vader is reborn and awakened shortly before Padmé's very public - perhaps royal - funeral on Naboo. Palpatine is the emperor, and he was the senator from Naboo. He knew her for a long time, so would want to publicly show his sorrow, and blame this death on the Jedi.
Obi Wan, Yoda and Bail Organa dressed the body to make it look like she died with her children, who was this trick for? She had kept it secret for the most part, she tried to hide her bump. Palpatine knew, and anakin knew. This 'bump' at the funeral was so everyone looking on would know she died along with her children - Palpatine included.
She was a popular, very public figure. She would have been nearly celebrity. Darth Vader's reconstruction took time, Palpatine had every opportunity to learn of her death.
So, who ripped Padmé's life away?
Mr Plagueis. He's the guilty one, your honour.
Sidious believes he is dead, but Plagueis is the one who could actually prevent death. He's harvesting life force from people to keep himself alive, Padme was a convenient victim. Someone he could take, that would keep him alive, that would blind sidious to their being Jedi still being alive, that would allow the Jedi to resurge, that would allow the rebellion to overthrow the empire, that would result in Sidious death, that would play into Plagueis hands and plan for rebirth and redomination....
... because Snokes IS Darth Plagueis.