About awareness agree. But sometimes I see that some my posts doesn't fully cover mentioned topics (that mostly happens after months the post was published, because during such period of time you can find and learn a lot of things you didn't know before).
Agree that there is no starting point. The only problem is that a lot of fans are interested only in some aspects of the series, and the things which are not on the surface are very likely to be missed.
From lore side ZUN tried to do retrospection of old characters in FDS. About the whole series, well, he just does what he wants to do. Things just work, so he doesn't change them. What actually are "the things that made touhou as touhou"? For different people they are different. From gameplay side it can be from patterns themselves to scoring, for these things you can play fangames as ZUN doesn't improve these aspects. From music side, well, ZUN still does good music (but not everyone agrees with this) (+ Touhou style music exists nowadays). About lore and story it always was vague and "not perfect" and it was good for fanwork creators. From the side of doujin circles, "any Touhou work can be sold" was very important.
It is hard to say what ZUN actually wants to do with the series. Maybe the printing work ZUN is doing now will show us that?
Somewhat yes, but he works with some people (and asked some help with UDoALG and the patch for it). + Recently, he drank beer with some doujin circles, they could offer some help and ideas (if I remember correctly many of them + BeatMARIO asked to make games harder). Also, ZUN works with Ruw (does he care about the series and fans? The answer is obvious. But it is important to note that he didn't appear out of nothere), and already have a lot of contracts with semi-official (do all of them actually care abiut the series?). ZUN can become less lazy and begin to work more with people, but there are some things that would be hard to change for him.
For now I don't have such work to do. If you are not afraid of statistics and monotonous work, then you can try to make lists of all unique Touhou circles for each year (some ideas how it can be used were offered here). About less boring work, if you have access to QQ, I can offer you to count the scale of Chinese Touhou Doujin (make a table of all Chinese Touhou-only events (THBWiki's one is not full)). Or you can read some research papers and come up with your own idea for your research.