Something that has bothered me for a while is that Guilds lack any sense of identity in WoW. I'm talking in-game of course, not looking up guilds on external sites on Wow-progress.
The only sense of identity a guild has aside from its members and member ranks and the guild icon when you open the guild tab.... that's literally it. How utterly boring. Each of my toons are in a different guild and it doesn't even feel like they are, since there is ZERO guild identity in the game.
Since they removed guild levels, there hasn't been anything special about being in a guild to be honest.
I would love to see more focus on building a guild community next expansion. Something that makes each and every guild distinct and unique. Perhaps different guilds have the option of choosing a buff that members that that effect gameplay or something. Perhaps a zoned guild hangout lounge that is customizable and unique with building options.