All in all, I feel the need is more for a way to access the important stuff on a new character (because you're changing your main), rather than simply change classes.
I've been moving around between 3 main chars over the years, 2 of which are currently 110 and actively played, and I don't want to drop one altogether, I'd rather make it painless to switch mains.
I would like account-wide exalted reputations for previous xpacks (up to the last one, or maybe just the one before that). I don't see how that would imbalance the game, since no current content would be impacted.
If they're fun, they should be in the toy box as well.2. My main has acquired a lot of items. Including items that... you guessed it, can't be acquired anymore. Fun items, cool items or simple trinkets, books the stuff.
All valid points.3. Achievements are not account wide. "Oh but they are, you can look at..." - no, they're not, if they were I would not get the same "do 10 missions" achievement in Legion my 5th time in a row. If they were I wouldn't need to worry about which char I kill rares around the world as another char is closer.
Here are two good examples:
- the fish 100 fish from Draenor, on which I have no reason to fish with other chars than the one I have fished most as they don't add in the end, so fish fished by a fisherman with less fish are wasted.
- the guild achievement points thingy - the char I like most still has their true achievement points count there.
So, achievements are not truly account wide, as you can get them multiple times and your char achievement count still exists.