Assassination ? I don't think you can assassinate a criminal. Isn't that word saved for people with some dignity.
The American Heritage Dictionary wrote: defines "to assassinate":
. . . to murder [a prominent person] by surprise attack, as for political reasons;
Oxford English Dictionary wrote:The action of assassinating; the taking the life of any one by treacherous violence, esp. by a hired emissary, or one who has taken upon him to execute the deed.
As much as the movies would like to paint him a hero, wasn't he a murdering bank robber. Oh, yes he was. A poor misunderstood bank robber who really didn't mean to kill. Wikopedia: "Jesse deliberately shot a bystander student of William Jewell College", and during a robbery of the Daviess County Savings Association in Gallatin, Missouri, he shot and killed the cashier. He became such a public figure that the stupid politicians, (even in those days) almost granted him amnesty. Politicians still cave to public pressure and polls. Murder is murder whether its a bank cashier a student on the street or a 7-11 clerk. I hope this isn't a pure glorification of the legend. Does it show him as the good here, super cowboy guy or does it get into at all some of the bad things he did to innocent people? Does it show the bad things that happened to his family to justify the bad things he did ?
Saying that, I love a good movie, even a good cowboy one. Can't count how many times I've seen Tombstone and so on. Just something about a man who can beat up on a guy for looking at him the wrong way

No really it's about the freedom of the wild west really. Riding those horses in the open country, that dramatic orchestra. Those were the days, no internet, no Wal-Mart, no toilet. You had kids for one reason, to work them day and night in the fields:) No, really, all kidding aside.