I'm going to do the work soon I just want to know if its going to be over here or not.
No one has any objections to you gathering up threads that people use as resources when building characters. However,
every handbook is a resource people use when building characters. If there is a difference between the two types of threads you mention, then you have not managed to communicate it. In your words a handbook "rate options for characters", but your Optimised Races Niche Compendium is a thread people would go to to find which races are good; thus by that definition it is a handbook.
The only difference I can see between that thread and the Race Handbook is that the latter is incomplete. You said that threads on "a class or class feature type" are handbooks, then said that
a thread on artificer item crafting was not a handbook but
a thread on item crafting in general was.
If the regulars here can't see a difference, how is an outsider expected to?
"I'm looking for resources on building a warlock. Hey, this section says it's Resources! Nope, BG doesn't have anything on warlocks." Those are the main audience, and confusing them would defeat the point of the threads existing in the first place.
The name "Handbooks" isn't any more meaningful than the name "swordsage". It's called that because many of the resource threads people wanted to save from 339 had "handbook" in the title, but that is not a requirement (e.g.
"Warlock Information Compilation"). It could probably have a better description than "a collection of handbooks", mind.