Bank view
That would be very helpful! In the meanwhile if you’re drowning in bank expresses as I am you might spend one now and then to check. Or keep a separate list, be it Excel or pencil and paper, to track the things you care about (way too much work when the game could just tell you).
That would be nice.
The closest you can come while out playing is to open up your hero panel and then go to crafting. If you have the right type of crafting on your char you can see how many items you have. For example, if you have a crafting profession that uses iron, you can click on iron ingots, as if going to craft them. It will tell you there how much iron you have and how many ingots already.
It’s a clumsy solution and you have to have the proper crafting profession, but it’s better than nothing.