Why spy alts? What would you gain with that effort? Nothing valuable nor important because if it is pve, then its restricted by faction and if it is pvp, its just plain murder. Or you expected someone to spy tactics? Or economy? What use is it to you to know what the other market prices are? Nothing.
Solution: Keep your nose on your own business.
Why bank alts? There is already a bank. You can expand it with bags. Got an awful lot of equipment? Not possible unless you loot every single item AND keep it, which is not productive and its only a waste of space. If there is something better get rid of the old. If you want profession mats then gather what you need for what that char uses.
Solution: I dont even know why someone thought about doing this.
Why multibox? Seriously... the "MM" part of MMORPG stands for Massive Multiplayer. Now tell me, where is the point of using 5 characters at the same time to play with yourself? The idea of playing this is to depend on other people for things that cant be done by just one. You want a full party by yourself? Go play FF or Baldur's Gate. Also, for what? You'd be just leveling slower, needing more mats if you want to craft them things, exploiting the farm (you need to kill more AKA not let others kill and monopolize the spawns), needing more gold to buy them things or train them. That would only rise the prices in the AH and you wouldnt even contribute to it, you become a sink.
In resume: You only help yourself draining from others. A parasite. And you can't even do end game stuff because you cant multibox in BGs nor Raids, its pointless. (No, don't tell me you can, its not possible, pvp requires dynamism and movement while pve requires tactics and timing, nothing of that can be done when multiboxing.) Or wait, you also expected to run dungeons and raids by yourself and ninja everything for your alts?
Solution: Do i need to say anything else? Be a man, play one character.