Some of the things below I'm thinking of as I write so sorry its a bit long and rambling!
Chat
Chat boxes just get filled with spam, and a bit like the Off-Topic forum couldn't that be used? Or if you want more of a live discussion then theres a Legacy Discord and GW Global Discord. Sure you need another account but it can be accessed in web browser, it is linked to from here and is already populated and moderated and most importantly active.
On the topic of Discord; what is happening with the Guild Wars Legacy Discord? Is it linked to this site any more? Is it linked to GW Legacy Guild/Alliance? Is it linked to the GW New Hope group? Mr Crow seems to have set things up but it hasn't been very transparent.
Forum Layout
Forum wise I think there should be less sub-forums, not more. The current ones could even be consolidated.
For the Builds and Content; Individual, Team, Farming, Speed Clearing could all be put in one that then becomes more active.
Can we bring back the labels/tags for threads? That way you could have one Subforum with tags to identify the threads. Individual/Team/SC/Farm/Chest Run etc.
That way you don't have multiple low activity Sub-Forums but have an easy visual for the topic of individual threads.
Streaming and Video and Creative Works could be combined into one as well.
I don't think it is necessary to have as many/the same sub-forums as GWGuru used to have. There just isn't enough disucssion and content these days to have it separated out.
Guru Archive
Is it possible for you to see how many hits the Guru Archive gets and which parts of it as to its usefulness? Would it be useful to remake guides and information on Legacy and remove access to them on Archive if it is a lot of space/cost to upkeep. Maybe having a Guru Archive while historic isn't the best because it means people don't have to create new content.
Guides
Alot of PvE players are making interesting guides and build theories to try and now optimise and improve as much as possible, but people have taken to using PvX and GWSC wikis(?) (wikii?) for creating build guides rather than posting them here. Could cross-posting even be considered as it might make them easier to find and be commented on/discussed with different areas of the community. Maybe discuss that with the people making them. I see Krschkr used to post some Team Builds on Legacy but now posts to PvX and Reddit.
Xunlai/Trading
The trading forum seems like the most active part of the forum, could there be any improvements made there? I see that auctions are mentioned in this thread, but trading via forum always seemed to be preferrable.
You have in the sidebar the trading rate of Ambraces to Ecto; how often is that updated/how accurate is it? Is it possible to do the same thing for Platinum to Ecto?
These days a lot of people seem to trade in Ecto, even for items that are lower-end. I think it would give some clarity to that for people that might want to do trading but don't have stacks of Ecto and aren't au fait with daily trading rates.
As with the thread tags I mentioned above, could they be introduced for Selling threads to identify when peope are selling really high-end stuff. Allow people to have two threads one in each tag so they can list things and people have an idea of prices.
One of the things with GW trading is it can take a long time to understand the market, not just the price of something but what is worth something and what isn't.
This would be something an auction based site could do if it tracks prices and can average them, but being able to accurately price-check items based on what they're sold for could be really handy.
Forum Content
Mods forum should be renamed to In-Game Modifications/Applications for clarity. Put in some effort to find, host, and explain the more useful texmods. Make a proper guide for setting up and installing umod for GW with an FAQ. Have proper info and examples of the good texmods as Wiki isn't the easiest place to find info and is pretty outdated. You could also have a request a texmod option if there are people out there that would make such things. Now that we're into the stage of the game where QoL things are much more handy people may have good ideas vs turning your bow into a banana.
Legacy General
What is the Articles link in the heading in comparison to the Legacy News forum, couldn't just one be used?
Social Media link on the heading only links to Facebook groups, could that be renamed?
There are 8 people in the 'Legacy Team'/Moderators but I don't think it is that clear what their roles are and how they are involved. Guru used to show the forum moderators on the forum list but this forum doesn't do that. Maybe a page/post with the brakedown of their involvement.
There was a lot of commentary and discussion about the recent Wintersday competition teaser on Reddit/Discord. Some thought into how to publicise future Legacy events with a decent level of transparency.