Transferring items between alt characters

[Niwashi]

Why would you guys even consider spreading out the classes when they all share skills?

They don't all share skills. Certain combinations share skills. If, for example, you had one character doing DoW classes, another doing DoM classes, another doing DoH classes, and a fourth doing DoL classes, archer is the only class that you'd duplicate in order to provide cross-class skills, as it's the only class whose cross-class skills cross the DoW/DoM boundary. (Then you'd duplicate whichever combat class is your favorite on your DoH/DoL characters, but they'd only need it for unlocking leves, so it's not like it has to be maxed out or anything.)

Anything duplicated beyond that would be just for whatever you find fun enough to want to repeat.

According to what statistics?

I'm guessing just based on the fact that that's what a Standard Subscription gives. (I don't actually know how many players keep their Standard Sub, though, versus how many drop down to an Entry Level Subscription.) Anyone who keeps a Standard Subscription is paying for the right to have eight characters per server.

No min-maxer will be making more than 1 account because of cross-class skills,

(I'm assuming you meant "more than 1 character" here, since that's what's relevant to the discussion.)
I've heard from plenty of hard core min-maxers who make multiple alts and get all their cross-class skills on each of them, because with multiple alts you have multiple chances at the top dungeons, more chances for loot, etc. It's a way around lockouts and caps.

and no casual is going to waste time redoing the entire main storyline quest and transfers all their work when they can switch out their gear/class with a click of a button.

A lot of casuals make alts precisely in order to redo the main storyline. The main storyline is the fun part of the game. Everything else is just grinding. There are plenty of players who like to play the fun part of the game more than once. This is the primary reason why I have multiple alts myself, (with RP being a distant second).

you'd be unable ... to use any of the already spirit bonded /used or "unique" (dungeon / chest deops in colours) items anyway on any alt so pretty much pointless

Despite quoting it, you clearly missed the part where he said "and she's maxed-out her crafting". The whole point of leveling up crafting is so you can craft stuff. That's brand-new, never used or bonded, fully tradeable HQ gear we're talking about. Of course his alts can use it.