Christiano Moreschi wrote:
No, of course not. That's perfectly fine, at least in my opinion. Nothing wrong with a list of those above 8 feet.
What IS original research is to pick a completely arbitrary definition of "tall" as being above x.y metres, and then to go on and use that.
I don't really see a fundamental difference between these two cases, however. In one case the arbitrary height cutoff is given in the list's title, in the other case it's given in the first line of the list's description. The same level of "original research" is present in both cases (a level I consider to be "not all that much" since height is a commonly mentioned biographical statistic for people who are unusually tall, I assume none of the heights of existing list entries had to be figured out from indirect evidence).
The only situation this seems significant in is if there were some need for disambiguation, in which case [[List of tall men]] could be turned into:
*[[List of men over 8 feet tall]] *[[List of men between 7 and 8 feet tall]] *[[List of tallest male basketball players]] *[[List of tallest men in medieval England]] {{disambig}}
Or whatever else the specific articles happen to be titled.