Read sections 1 to 3 for now... great work !
Looks incredibly good for noobies. Definitly deserves not only to be sticked, but also to be referred to from the wiki or/and game's help menus : such awesome work isn't of any use if beginners don't know about it.
I got a few feedbacks :
Gun's Alternate fire : I think aimed shot takes "only" twice as much time as a regular one. You could also mention that accuracy bonus is +3, which is significant (without going further, ofc, but just to give player a rough notion about how accuracy works, rather than just "improves accuracy")
You forgot to mention double shotty's wide area. imo, it's more important than the 9d3. I don't know if telling that 2nd shell is fired after knockback occured is necessary (but it would help understand why this weapon sucks after a few tiles of distance. reminds me of a recent post about phobos lab where one complained about the shambler's near immunity vs double shotty... he just overestimated the weapon, I guess))
Chaingun's chainfire isnt 3/4/5, it's 3/4/6.
For plasma rifle, it's 4/6/9
I think you should tell about mancubis's slow react time when player gets out of LOS (i.e., the fact that it'll still fire once)
The shotgun ranges picture for area of effect is very nice. Maybe it could be improved with something like degrading colors from green to red (to show focused better efficiency at max range), but it's already very nice, even if it might not be fully accurate of real area.
About traits :
WK : you may precise that melee weapons only accept 3 different mods (like armors). I never play melee, and this surprised me about every time... when I wanted to put a 2nd bulk or power on my chainsaw.
SoB : "It's pretty much a waste of a trait for shotgun and melee builds" Ok for melee, but Shotguns... I don't think I'll pick shottyhead a 2nd time, now that I noticed it blocks SoB.
Also, I think SoB is superior to TH, for several reasons (saves ammo rather than wasting them, which also means less reloading necessary, better against armored targets, works on all weapons...). If I'm right, it should be told than SoB is better, since an "advanced" trait should, instinctively, be better than a basic one. (Writing this makes me wonder if TH shouldn't become the basic and SoB the advanced one... I would hate it, of course, but I think it would be much more balanced : 99% of my chars start with SoB now, only melee & pistols build don't)
SoG : maybe precise that gun's main weakness is reloading time. This makes much more obvious than DG isn't a solution, since it just lowers shooting time, but doesn't improve ammo efficiency, as SoG does.
EE : distance (-1 to-hit for every three spaces distance) -> isn't it -1 every 2 tiles ? I recentely checked wiki's accuracy page, and would swear it's what I read.
INT : LOS + 3 ? Int2 reveals at LOS+2, not 3 ?
MMB : Mention butcher's cleaver, which is a blade (Also, I think piercing chainsaw is THE melee assembly. I don't care about the other... but I might be wrong on this)
Overall, you seem to value Tac armor a lot... I love it too, but try to avoid it now, since it doesn't prevent YASD. I think it's better used with intuition (be it the trait or 2dev's one), when playing carefully is enough to avoid being surprised by a mancubus.
Else ? I always go for one (or more) cerberus when possible. (Necro, Malek, or good vests/shields are alternatives, since ms is very important, but they aren't guaranteed)
Also, I don't know if you mentionned masterless builds. I think you introduced things like "choose a mastery first", but as I said with Shottyhead, masterless build can sometimes be a great choice, since most masteries block useful skills.
I'll continue editing my post once when new sections come, to avoid spamming the thread.