Currently, we're allowed to make several characters on each and every realm -- and fill them all with items. As such, this means that you have plenty of disk-space on your servers to handle the load. But I don't want 1,000 alts with random gear, I just want to be able to keep the items that I've spent months working to earn, without being forced to trash them.
Your current inventory setup directly penalizes players who have been playing since release. I'm sorry, but I worked my ass off to get my tier 0. If I want to pull it out of the bank and wear it around town once a month just to show off my oldschoolness, I should be allowed to. (And lets not forget that my entire tier 0 probably takes up less than 2-3 kb of disk space on your server. We're talking about less than a penny's worth of disk space.)
Additionally, new events are constantly being added that intentionally give players collectable items. Even the venders refer to them as "souvenir's", which litterally means "A token of remembrance; a memento." (Dictionary.com) However, we're not given additional bag space at the rate at which new souvenir's are added.
Just to emphais this point, consider non-combat pets. Currently, there are 75 non-combat pets in the game, and more are being added. Suppose, for example, that the Warrior mentioned above wanted to collect pets when he or she wasn't raiding. That person would simply not be able to, because they barely have enough room for their raiding gear, and they have absolutely zero room for souvenir's or vanity items.
The Solution (Quick and Easy)
Allow players the ability to earn additional bag space in the bank. For example, allow players to purchase as many bank slots as they want, for 150g each, past the price of the normal set of slots that we have now.
Result: Players who have been around since release would be able to earn room to keep their hard-earned souvenirs. Also, this would greatly help the economy, because gold would now have additional value, and because tailors would be in demand to craft more bags (If a player is paying 150g per bag slot, they won't mind getting a good bag to go in that slot).
This solution helps everybody.
From a business standpoint, why would you turn down such a simple solution for making your customer-base infinitly happier?
Nobody's asking for free hand-outs. We're simply asking for the ability to progress our character's ability to retain hard-earned items and souvenirs through our gaming dedication. =P