I'm a UK user but hopefully talking about common experiences. With a massive family tree - I'm using the 'Hints' list more and more frequently but finding there are some silly issues which, without extreme caution, could lead to false lines and are at least time consuming to deal with.
If a female is listed, on a census, as married - it is extremely unlikely that she will have the same surname she was born with. It's not impossible but it would be nice to be able to toggle, via user settings, improbability on and off.
Also, if a person has a citation link to a particular year's census return, it's unlikely that they would be in two places at once. Theoretically it's not impossible (I have seen a couple of cases of the same individual being listed twice) but, again, some sort of toggle would be useful. It's exasperating to have that leaf come up, get all excited about a new hint, and discover it relates to an event already source citated and just.. wrong!
UK census returns were taken in the spring of the second year of the decade (i.e. 1851, 1861 etc.) and the date of birth this confers can lead to a majority of erroneous hints from the birth indexes. What I mean is: if a person is, for example, six years old in 1871 then that gives a birth year of 1865 but because the census returns were taken in the spring the balance of probability is that the person was born in 1864. An automatic 1865 date is fine but then the hints page gives preference to birth listings for 1865/1866. If the hint says the person was born before, say, March in 1865 then chances are the hint might be correct - but wouldn't it be better to take that "abt 1865" birth date and translate it into birth index hints that start in 1864? As it stands now - I've started amending the year of birth, from the census return, by automatically putting it back a year. This is creating problems, for me, because I have no way of remembering if it's one of my amended "abt ****" dates or a date straight from the census - so this is not the best way to do it.
"People with Hints" - Filtering Potential
With many thousands of individuals in my tree - it would be nice to sometimes focus on 'completing' the available historical facts for those that are more closely related to my direct ancestral line. It would be great if, upon fetching up that list of "People with Hints", there was a way of filtering (as is possible with FTM) something like ancestors for five generations, their children and their grandchildren - and get hints for any probable facts that may be obvious by being missing from the individual's source citation list.
These are just a few ideas, that others may agree, might improve the efficacy of the Hints List.
Ta very much :)