Presumably, this would require the implementation of some sort of "icon creator", maybe put this on the back-burner for now as it's purely cosmetic and not as essential to the guild system as other features. I like the idea, but fixes of current issues should be prioritized over developing things that only give small, unnecessary changes as a result.
I believe that guild members should be inviting players, not the other way around. Not only is this standard across most games (and thus familiar to players without explanation), but it avoids problems like guild staff being spammed with players attempting to join (these would probably have to sit in a queue of some sort leading to more necessary code to support this function, as well as being less clean than just a guild inviting online players), and would likely lead to easier ui/ux implementation (e.g. a member would click on a player to invite, but in the reverse case, a guild-less player would click on a player in a guild, then request to join the guild through them (or by typing a likely case-sensitive name which is already annoying in itself).
Price seems good, but maybe consider other requirements such as account age, character level, or something else that would add another progression element to the game.
Permanent name/banner seems pointless. Allowing them to be changed (for electrum) adds an additional revenue stream to HH as well as adding convenience for guild owners (could you imagine having to kick everyone from a guild, delete the guild, create a new one, re-level it up and invite people just to change the name?).
I like this. Another idea would be to supplement a straight XP grind with challenges/milestones, potentially as a capstone for each level (e.g. going from level 5->6 requires 50,000 experience points and complete the challenge: "Defeat T5 Hard boss 10 times"). This not only adds more "content" to the game, but it would foster a better sense of community as players would likely end up working together to achieve these challenges (and would eventually have to as challenges become increasingly difficult). As opposed to players being able to play individually and still contribute xp to the guild. This could be trivially implemented by reusing the existing challenge/achievement code.
Blue on map is good stuff. An additional chat tab would be a nuisance with the chat box in its current state. It already is buggy (for me anyway) and only supports normal global chat + combat log, before you need to use the arrow to access additional chats, which in my experience has been buggy/fails to work frequently.
I like this concept, but agree with Nojaw. Player caps should be proportional to the community of the game and should be updated as the player count changes.
I agree with this entire section. We need more end-game silver sinks, this seems reasonable, straight-forward, and relatively easily to implement thinking of already existing functions in the game (legacies/t9 boss buffs code could be reused).
I definitely definitely agree with Nojaw. The idea of a competition is cool, but we can't have that one guild full of unemployed virgins winning every week. Some sort of cap needs to be implemented if directly competing with other guilds, or, drop the competition and just make it a weekly resetting goal that multiple guilds can achieve. Either way, I am hesitant to make electrum this easy to acquire (both for the economy's sake, and for HH's bank account's sake). Perhaps giving out bloodstone and a smaller amount would be more appropriate.
Leaderboard is a good idea and could be combined with the well leaderboard potentially.