If they were better explained before, what's the need for an explanation now? Maybe they left it up to you/your RPed character to decide...

(I'm one of the ones not troubled by Legendary statuses)

1.) SS had too many chems or maybe being frozen for two centuries screwed up their mind? Would the supernatural count as magic?

2.) Well, you did a good job explaining it yourself.

3.) Lucky hat. Well, maybe there is a four leaf clover inside of it? Maybe Cait might have worn it in the past and brought Lady Luck and/or the Luck of the Irish to it?

Endurance is partly a measure of how much damage you could take and leather is pretty tough, not to mention have you seen how sturdy that leather looks when you have it equipped? Imagine elbowing or shouldering someone in the face with it.

Yep those are my flawed explanations right there!

I completely agree that different ammo types would be more logical. At the same time I can't imagine having to carry around 5 or more types of each kind of ammo with me all the time and find time to switch to the right ammo for every attack (I never even bothered in FO-NV). Course I'm also carrying around weightless ammo ... which, knowing how much a full ammo box weighs ... is total BS.

I suppose for ease of game play something has to give, but I still think the magic guns are just too much. But like I said I sell all my legendary anything so I don't have to think about it.