The laws of all the states are quite similar as far as what constitutes justifiable self-defense. I'll quote from Steve Johnson,
Concealed Carry Handgun Training, North Carolina Justice Academy, 1995, pp. 3-4 (the laws in Florida are similar, but this is the best wording I've found):
(1) Justified Self-Defense
A citizen is legally justified in using deadly force against another if and only if:
(a) The citizen actually believes deadly force is necessary to prevent an imminent threat of death, great bodily harm, or sexual assault, AND
(b) The facts and circumstances prompting that belief would cause a person of ordinary firmness to believe deadly force WAS necessary to prevent an imminent threat of death, great bodily harm, or sexual assault, AND
(c) The citizen using deadly force was not an instigator or aggressor who voluntarily provoked, entered, or continued the conflict leading to deadly force, AND
(d) Force used was not excessive -- greater than reasonably needed to overcome the threat posed by a hostile aggressor."
(Emphasis added.) Note that all four conditions must be met in order for a shooting to be ruled justifiable. Note especially letter (b) above, which is the "reasonable person test"; merely "feeling threatened" by someone else is not justification for the use of lethal force. The belief must be legitimate, i.e. "the facts and circumstances prompting that belief would cause a person of ordinary firmness to believe deadly force WAS necessary to prevent an imminent threat of death, great bodily harm, or sexual assault." The new Florida law does not change these criteria, it just eliminated the subjective duty to run away that was present in Florida law even in the face of a lethal attack.
Florida, and many other states, also authorize potentially-lethal force to stop the commission of a "forcible felony," as defined by statute; such would include kidnapping, armed robbery, aggravated assault (i.e., assault likely or intended to maim or cause serious bodily harm and that could result in death), etc.
OK, now to the recent law that eliminated the "duty to run away" requirement that had been in Florida law, and also extended the "Castle Doctrine" (the presumption that if someone is illegally breaking into your occupied home, you are in danger, which is already law in most states) to your vehicle.
In the case of the drunk with the bartender, it would come down to just how serious the threat from the drunk appeared to be, and just how imminent the threat was, and that would be true in any state. The thing about a claim of self-defense is that the burden is on the
shooter to demonstrate that the shooting was, in fact, justifiable, rather than on the state to prove that it wasn't. So if a case is questionable, it tends to swing against the person claiming self-defense.