Here's what I got:
Population disparities between New York City and Boston
Needs Improvement. I like this question a lot. However, a request for a slightly better rewording in the comments went unanswered. Also, I pretty much had to enter the entire title before Google found it (top hit when it did though). But the worst problem is that none of the answers were ever accepted. The best answer of the bunch IMHO was really too short. Given the user's rep, its unclear they are around enough to even accept a good answer if it appears.
Oldest appearance of "brand names" in history?
Satisfactory. Its worded a bit too much like we are playing a trivia game, but otherwise a very good question. It has a good accepted answer, although one which is worded a bit too tentatively for my taste. Its main problem is that I had to add the word "appearance" to get it to show up on a Google search.
When the term "president" was used the first time?
Needs Improvement. An interesting question, with a very good answer. However, there is only the one answer, it has not been accepted, and I couldn't find it on Google even when I search on the exact question title.
How did the Dutch East India Company (VOC) have so much revenue when they only control small part of Indonesia?
Satisfactory (barely). Somehow I missed this one when it was asked. The question itself could use a little cleaning up. As it is, it seems to be asking "How do people make money out of trade routes?", but could probably be tweaked to be more specific to the VOC. It has three pretty good answers, but again none have been accepted. It shows up fifth in the dumbest Google query I could think of on the subject, a pretty darn good performance.
To what extent did the CPC avoid fighting with the Japanese?
Needs Improvement. I could see a tweak or two to the wording, but for the most part the question is great. Best of the bunch by far. It also is the top hit for the first Google search I tried. However, the only answer at present is negatively voted. It looks to be an eminently answerable question, so there is really no excuse for this.
Prominent examples of scientific racism in ancient Greece
Needs Improvement. IMHO the question is too long, with way too much quoted material. Other than that complaint, it is a great concept for a question, and very well written. It is also top hit on my Google search. It has a fairly good answer (lots of upvotes). That's where the good news ends though. There was only the one answer, it is probably too emotionally worded, and for whatever reason the OQ didn't find it acceptable. I'm giving it the NI purely on the lack of an accepted answer. There's a very fine line between this question being excellent instead, but it presently falls over onto the bad side.
How did ruffs become fashionable and then went out of fashion?
Needs Improvement - Judging by my past votes, I personally like this question and its top to answers. However, judging by the other votes they all received, that doesn't appear to have been a common opinion. It was about the 9th hit on merely "ruffs fashion", which I consider pretty darn good. Again, none of the answers have been accepted. Again, I'd have changed my vote to "Excellent" if not for that fact.
What factors led to the 30% devaluation of pound sterling in 1949?
Needs Improvement - Another one I missed while out of town. I like this question, although it is of a dangerous variety, in that it tempts speculative answers that don't rely on consensus historical opinion. The top answer IMHO succumbed to the temptation. The next answer is much better. The question showed up 5th on a simple Google search, which is really pretty good. However, again no accepted answer.
Did the civil wars of 17th century England facilitate an independent spirit in the American colonies?
Needs Improvement - A very well-worded question, although one that is sadly a bit squishy. The sole answer avoided this sandtrap by instead devoting itself to describing the buildup to the American Revolutionary War, as if a question about that was asked instead. It was (probably rightly) not accepted.
What is the significance of roof charms outside of the Forbidden City?
Excellent - A great question. Just the kind of thing SO sites are needed for. I remember researching this myself, and there really was no straightforward answer to be found on the internet (I know I commented otherwise at the time, but that info really had to be coaxed out). The accepted answer could use some tweaking, but is pretty good. Google found it on the 4th hit. Biggest issue is that there's only the one answer.
Final analysis: The Achilles' heel for the stack here in my evaluation seems to be questions with no acceptance. I'm kind of hard on this one, because I know when I'm searching and hit other SE sites, I don't find questions without accepted answers very helpful (although sometimes an extreme amount of upvotes will do instead).
In some cases the lack of an accepted answer may simply be due to the questioners not hanging around to maintain their question, but at least a couple of cases appear to be due to no "acceptable" answer being posted.