Blizzard recently added guild banks. Sure, guild banks are awesome and they remove the practice of keeping tons of junk on someone's personal mule account, but they are a security nightmare. Managing ranks and access to bank tabs is done through a pretty poor interface.
As my guild has grown, I have seen the need to add some more ranks just to manage access to the bank and give people more control over promotions, etc. You can't add a rank in the middle, you have to add a new one as the lowest rank. The lowest rank is the rank all new members join at, so you need to do the membership shuffle. Moving everyone in your guild down a rank. Time consuming and not a fun thing to do in the game. Something as simple as adding a rank can net you several hours of monotonous clicking, the kind that won't get you any XP or gold. Blah.
I also want to give out the ability for officers to withdraw cash for buying raid supplies or payout out for contests and such. But our guild doesn't let people repair out of the guild bank. Right now the guild management lets me restrict people to only being able to pay for repairs out of the guild bank and not withdraw cash. The exact opposite of what I need to do. So, there are always issues where someone accidentally clicks the wrong button and they have to pay back the costs to the bank. It's the little annoying bugs that often end up being the most frustrating.
There are a million other things in the game that I know Blizzard will spend time fixing and balancing. I understand that. But guilds are practically a requirement for playing the game beyond hitting the level cap. These guilds aren't going to run themselves. Making it easier to manage a guild and keep the bank secured means pleasing the minority of people who are pouring their time and effort into providing a better game experience for Blizzards customers.