All given various, sometimes plausible/sometimes not, reasonings for suspicion. It has even been proposed that all were not committed by the same hand, though five are pretty much attributed to one.
The following is merely my opinion from what I’ve read.
It’s not so much who did the actual murders, but my ‘conspiracy’ as to why they were committed.
I believe it did involve the crown, specifically Prince ‘Eddy’ (Prince Albert Victor Christian Edward..) It has been inferred that he was gay and involved in the Cleveland Street Affair. If so, and a few prostitutes knew of it, and possibly had some proof, to save the embarrassment of the
crown and the fact he would have had to stand trial, as homosexuality was considered a crime punishable by imprisonment (as was done to Oscar Wilde), their silence would be 'arranged'. Especially, if undeniable proof was given, it could cause a great scandal, so any threats were eliminated in one way or another.
Perhaps the murdered prostitutes tried blackmail. Who’s to say.
Catherine Eddowes, who also went by the alias ‘Jane Kelly’, was perchance killed mistakenly for ‘Mary Jane Kelly’ (though they looked nothing alike), and perhaps the perpetrator had some remorse and that is why the actual Mary Jane Kelly was mutilated so horrendously, or was it merely the murderer was given privacy and uninterrupted time?
Also, concerning Montague John Druitt (who plays an important role in this imo, as you will see), was considered at the time to have committed the murders, and supposedly chose suicide. He was also believed to be gay, and if he frequented ‘Cleveland Street’ and perhaps knew of, or was even intimate with the Prince, his supposed ‘suicide’ made him the perfect scapegoat?
It is suspicious that rocks were found in his pockets and that the police made the statement that the Ripper was dead, after finding his drowned body in the Thames.
(And it kind of annoyed me with the show 'Sanctuary', making him out to be the Ripper.)
Anyway, the fact that the entire case was handled so shabbily, and only late did the Queen comment on it, I feel it was all a cover-up to protect the honour of the crown. Especially since much of the evidence and paperwork was 'lost'.
I think the true identity of the Ripper was known, perhaps even hired, by a select few to protect the crown. Threats may have been made to those of royalty that might have known, and the poor misfortunates were simply eliminated. Why it was done so brutally? To spread fear and keep mouths shut.
K, that is my thoughts on it.
My best friend has told me I should write a book about my theory, problem is someone like Patricia Cornwell ('Portrait of a Killer'), for instance, is a seasoned author and had funds at her disposal to travel the the UK/Scotland Yard and pour through what documents survived, to have DNA samples taken from letters and sequenced or whatever, even purchased one of Walter Sickert's paintings. I do not have the means to do such research, therefore, all I could do would be write it as fiction. And I'm not even that good of a writer.
I did, however, have an idea for a Jack the Ripper film, which I will post sometime in the near future, along with some of my Ripperabilia. Yes, I find the case very interesting.