I've been busy with rl and almost forgot about this thread... Time to tally up the results, since there are enough votes (143 to be exact).
Even with the imperfections that have been mentioned in this thread (and others), imo a safe conclusion from the poll is that most players prefer 20 cities or less in their average game of Civ VI. While this is less certain, 1-5 cities and 100+ cities seem to be outlier cases that are favored by players with specific playstyles; they either want to turtle safely at home or rule a significant portion of the globe in most of their games.
If we take the portion of the voters who favor 6-20 cities, it constitutes 72.03 % of all votes; i.e. over a 2/3rds majority. If we include those who favor 20-25 cities, over 3 out of 4 voters fall within this group (6-25 cities). I suspect that people's votes within this group might not be hard and fast, but vary based on their mood and allotted time for each game. So someone who voted e.g. 11-15 cities might favor 20 cities next week. There is a clear divide at 20 cities though, after which there is a steep drop in votes until we reach the special case of 100+, which drew 12 votes total (disregarding an erroneous vote by a single voter). So, 20 cities seems to be a kind of threshold that people are reluctant to cross in a regular game. As was pointed out to me though, after 20 the finely grained options of the poll work against the tendency of the human brain to think in tens (or logarithmically) when it comes to bigger numbers. So the structure of the poll might have thrown off some people who would have voted for 20-30, had it been available as an option. I will remake the poll once we get closer to the game's release and we know more about the interface (as its suitability for larger numbers of cities is a major factor in how people will vote). For now though, let's assume that 20 is the maximum number of cities that most players will tolerate.
There was at least one player who favored 1-city challenges, and 10 people in total have voted for 1-5 cities. (It would have been interesting to know how many voters meant specifically 1 city, 2 cities, and so on; when I'll remake the poll, I will start with single-digit increments at the lower end.) I suspect that people might have voted more for this option if it wasn't for Civ V having burned us out when it comes to small empires. Imo, it's time to think big again and put the 'eXpansion' back in the '4X' concept.
This said, perhaps some players who think this way now would change their vote after a few months of playing with bigger empires in Civ VI; a third poll might be in order after the game's been out for 6 months or so.
The 1-5 option was still popular enough that it should remain viable in Civ VI to make do with a smaller empire, imo. But I have no qualms with it being a bit harder than making a medium-sized empire (6-20 cities), because in Civ V it was the opposite, and a perfect balance seems to be a pipe-dream in such a complex game.
If 6-20 seems like too wide of a target to hit, it's worth considering that only 13.29 % favored 16-20 cities -- a significant drop from the 24.82 % in favor of 11-15. I'm not good at calculating weighted thingamajikers, but a quick eye-ball seems to indicate that Firaxis should target something like 8-17 cities for an average game on a Standard map (based on this poll alone, which ofc would be an unwise basis for such a figure). That is still a wide mark to hit, but it should be possible depending on various random factors (neighbors, quality of lands, size of your starting continent, etc). Thus in an exceptional game on a Standard map you might get to have 20 cities, if you bothered, but could still make do with 8-12 if you wanted to and did not care too much for optimization (as most players won't; we here at CFC are a minority when it comes to playing 'optimally and strategically').
It's worth pointing out that the way the new district system works will drastically affect most players' votes; if it proves optimal to have 5 districts per city, you will need to settle more cities than if the optimal number is 10, etc. There may also be other factors influencing the 'real' result that we may not yet even know about.
In conclusion, it was too early to make this poll, but at least it serves as an indicator that 4-city empires as a regular occurrence are something that the game should move away from, according to a great majority of the players who frequent this site and are inclined to vote in highly speculative polls.
