They could probably add bags to the game that utilize your slots (each slot the bag takes is one slot away from your inventory)... Such that you can organize your inventory into these "bags" yet SE has barely added anymore server stress on their end.. But that would likely only be a neat feature to a select few.. and due to WoW many more probably complaining they don't function like actual bags as they might expect them to lol.

A mod I really liked in WoW was an auto complete search bar in my inventory space (that also checked my other locations at the end, like banks/alts, etc) so I could very quickly narrow down what I was looking for as if it was a music playlist. That'd be nice.