An interactive table for the inorganic materials, of which there is already a table in the manual, but cannot be sorted at a whim.
Also, Adamantine disappears from the table when sorting by name.
A table defining the different values of different weapons; both ranged and melee weapons need to be more clearly defined.
Right now it's pretty much guesswork as to what the difference is between a spear and a pike. And such. I also have no idea what a "giant fork" does, or whether or not it's more or less effective than a "pointy stick," or whether I should forego both and whip out a "pair of butterfly knives."
A table pertaining to the coverage of armors.
Since you added new types of armors, it would be useful to know each pieces coverage. Is vampire slayer armor more, less, or equally protective than simple leather armor? Etc.
A list of the required materials for a workshop within the 'workshops' tab in the manual.
This would both be useful for advfort and Dwarf-mode, as a quick glance at the materials of a workshop can help us place said workshop in a tech order.
Magic spells effects and cooldowns under the "magic" tab could be better defined.
And perhaps a mention that magic spells don't seem to work in adventure mode, or at least extremely ineffectively, probably due to a plug-in not loading in Adventure mode which is critical for temperature-and-poison-based damage in DF mode.
Better, more comprehensive lists and statistics of the added races. Perhaps a link within their paragraph to a new page containing that races raws.
And it might be a good exercise in creativity to re-write their flavor texts to not rip off World of Warcraft and The Elder Scrolls
^ But that's just insignificant bitching.
Maybe a quick, bulleted list of different types of reactions that workshops can run.
There are far, far too many reactions to list them all. And right now, there are paragraphs which describe what a workshop does, but it might be cleaner to the eye to view things as a bulleted list. Now that I think about it, this suggestion is redundant as the workshop paragraphs work perfectly fine for their purposes. But still, perhaps including more precise information in said paragraphs would be useful.
Essentially, much, MUCH more information could to be added into the manual since Masterwork lacks the comprehensive community-supported wiki which vanilla DF benefits from.