Sure, it IS to the point and describes the uses of guns, but I can't help but compare it to the Bomb guide which has a lengthy description of each bomb's mechanics, details in paragraph form of pros and cons of each bomb, and (most importantly) tells which bombs are good or bad.
The guide tries to be pretty objective and newspaper-like as it is now, but seeing as how the bombing guide already conveys massive amounts of bias against the bad bombs (and saying why) should we not also include similar info in the gun guide... why a gun is good, commonly used and is recommended?
Ideally we would also eventually have strategy articles on how to wield certain types of guns (i.e. one each for Pulsar, Catalyzer, Alchemers, Antiguas, Autoguns).
I'd like to help out with it personally, but editing a wiki scares me. :D
You can always team up with someone who is more savvy in wiki-fu to have them put in your edits. However, editing the wiki is not too bad once you learn the ropes. I would suggest that you just try experimenting with your userpage by clicking on your name (be logged in, of course) in the upper right of the wiki page. If the link is red, it will take you straight to the editing page. You can then try things out in there. It's even possible to secretly learn by only using the Preview button to see what different things look like and never hitting save. To see what wiki markup is on a particular page, you can click on the Edit tab and look without making changes. I will note that while there is complicated coding for tables and such, most guides are mainly just paragraphs of text.
Questions on how to do things are always welcome on my talk page or here in the wiki forum.
Here are a few pages that may be of help:
http://wiki.spiralknights.com/Help:Linking
http://wiki.spiralknights.com/Help:Creating_a_user_page