I could go on and on about the games I've played and the various guild banks that I've had access to and their various features. However, you didn't click on this link to read about other games and what they do or have done, or my experience in those games.
Simply put, this is what the Guild bank for the Elder Scrolls Online should be, rather then what it is now:
- Guild Banks should have Tabs that are purchasable with either gold or a points based system tied into the 'Guild Level'.
- Tabs should have the ability to be named. Ex. Provisioning; Raid Potions & Food; Crafting Materials.
OR
- Guild Banks should be able to be upgraded with space based upon guild membership. 500 slots is far to little for a guild that may be membership capped. Ex: 500 more slots at 100 members. 500 additional slots at 150 members. 500 additional slots at 200 members. etc etc
- Guild Banks should allow the Guild Management to set up permissions regarding access, withdrawals, & deposits, per Guild Rank/ Per Tab or even Per Member.
- Guild Banks should properly stack/re-stack any item placed into any tab.
- When viewing a particular tab in a guild bank, the entirety of that tab's contents should be viewable on screen, not via scrolling up or down.
- Filters should be added to the Guild Bank to make it easier to find and/or sort gear. Ex: Advanced Filters Addon.
- The ability to deposit cash into the guild bank, on ANY tab should be available.
- All guild banks need a 'Search' option.
- Guild Bank History needs to parse approx 100X more then it does now. A History that encompasses only the last 30 minutes helps no one. A History needs to show transactions by day & month. Each and every transaction.
- A Guild Bank needs to be able to assess taxes to all of the guild members. From 1% to 50%, taking taxes from quest rewards and loot drops, NOTHING ELSE.
- Permissions set with the Guild Bank should allow guild management to allow certain types of gear deposited or withdrawn. Ex. No White Items deposited; Deposits Only to Tab #2, etc etc. These types of permissions should able to be activated per tab.
This is just a small list of improvements I feel that the ESO Guild Banks should have. While I know some of you may not agree 100% with some of the things I have suggested, even a few of these changes or additions would improve the guild bank over what it is now. Even if that improvement is just extra slots.

Thanks for your comments!
Sinister Swarm
15 Years of Gaming Excellence