We're often torn when it comes to questions about alt progression, alt catch-up mechanisms, or account-wide systems. Philosophically, what's the point of an alt? For one group of players, the primary desire is to jump into participating in endgame activities from a different perspective (a PvP alt, or a healer alt for a change of pace from your usual DPS main, or whatever). In that context, almost any required progression can feel like a nuisance - an obstacle in the way to the desired endpoint of being raid-ready, or arena-viable.
For another group of players, an alt represents a fresh set of goals to pursue after reaching a point of diminishing returns on a main, whether that's someone who hits max level and then promptly begins leveling another character, or someone who doesn't have many available gear upgrades left on their main and hops over to an alt where progress can once again come quickly. For this type of player, the more things are account-wide, the fewer new goals they have to pursue.This is a good point on how there are two groups with opposing desires when it comes to alts. Fortunately, Blizzard has a game which has already solved this problem: Diablo 3.
Normally, new characters in Diablo 3 share a lot of elements: access to followers, crafters and recipes, and a common stash. But Diablo 3 also has "seasonal" characters, which are a new character which does not share anything with the others. The character lasts for the season, and at the end converts into a normal character.
This might be a good system to bring to WoW. Allow people to create seasonal characters, which:
- cannot use heirlooms
- cannot receive mail from non-seasonal characters
- cannot trade with non-seasonal characters
- cannot access guild banks
- do not share currency or reputations
- cannot be boosted
Then allow normal characters to share reputations, and maybe other elements like a common bank stash, or even currencies.
Throw in some achievements, and maybe a pet or mount reward for levelling a seasonal character from 20 to 120 (start at 20 so that you can level Allied races). Maybe automatically give out an old tier set cosmetic armour. That's enough of an excuse for people to try out seasonal characters. You can link the seasons to the PvP seasons, as they already exist.
I think this would solve the issue between the two groups of people who want to create alts. It would also create a new track of gameplay for people who are so inclined.
Personally, I really like Diablo 3 seasons. It gives you a reason to start a fresh character and level it to max, as well as several points where you can stop and feel satisfied with what you've accomplished. Seasons would be a good system to port to WoW, especially with all the new Allied Races.