Fandom strongly recommends that Category:Browse be renamed to Category:Destiny Wiki. In the past, Browse was standard, but more recent research has revealed non-descriptive words for top-level category names are really bad for SEO, and the sitename should be used instead.
The pages about the other 3 announced Destiny 2 DLCs have been created. Would you like to put them in the wiki navigation? I assume all the Destiny 2 DLCs can't fit into there, so you should probably select some one before another ones (old+present, present+future).
If MediaWiki:Common.js/countdown.js isn't used by the wiki, it would be advisable to move it to its author's namespace - User:Silicon_Soldier/common.js/countdown.js. I would wait till after the review process, so as not to confuse Fandom staff.
(And of course leave a message on User:Silicon_Soldier's wall, letting them know where their js can be found.)
Most users don't realize they can write their own personal js (in their own namespace), and it doesn't need to go through the review process.
It probably isn't a good idea to have a test page in the mainspace. While I doubt it would cause any significant issues beyond potentially messing with search engine results, testing is exactly what Destiny Wiki:Sandbox is for.
There's a few things that would be beneficial to clean up. I already mentioned these to M67PattonZippo while you were on your hiatus, but since you appear to be back, maybe you could look into them too. here is our discussion so far.
It took a bit of struggling, but I finally hammered them into the main page. For reasons I am not entirely sure of, the PortalBox template refuses to allow the icons to be any larger without stacking them vertically, but I guess it is fine as is as long as you are ok with it.
I hate to bring this back up again, but I received this note from one of the Content and Community Managers regarding this wiki: I suggest to improve a bit more the Main Page. They updated the Welcome template, but the description is still too vague and generic, and it doesn't help a lot the SEO. They have to explain better that they are a wiki about the Destiny series, and what is that series. In addition to the Welcome section, I recommend an "About Destiny" section with the starting info about Destiny 2 and/or the series.
I got some more notes concerning the main page. I recommend changing the Welcome message to:
"Welcome to the Destiny Wiki, the wiki about Destiny, an ongoing first-person shooter video game series developed by Bungie, where the players, known as Guardians, have been resurrected to fight the enemies of humanity, acquire epic loot, and become legend!"
That identifies the wiki as a wiki (for search engine results) and only uses internal links, to keep people from immediately clicking away to another site as soon as they arrive.
They also still want some sort of an "About Destiny" section with basic information about the series.
I am adding a Fandom University player to the Special:Community page to help out new or inexperienced editors on all wikis that are willing to accept it. You can see what it would look like on the Diablo Wiki. This is done with ImportJS and so can easily be removed at any time. Would you be ok with this addition here?