I have noticed many Cuusoo projects with an unrealistic figure count. There are many that outstrip the Deathstar and speculate half the price.
I know a large number of people flat out ignore these projects as unrealistic. Even if they were to get to 10k, Lego would not green light projects that are bad for their bottom line. Figs are VERY expensive (relatively speaking) for Lego to make.
So, I figured I would create this chart which might help people have some idea of what to expect when it comes to normal Figure distribution. This was generated by comparing the price, Lego brick count, and fig count of all sets released in 2011. Outliers were removed from the data, that being sets that do not have figs at all, battle packs (which are exclusively or near exclusively figs), and calendars.
What does this mean to me?
I implemented a lot of rounding here because I think the stronger message is scale rather than the specific fraction of a minifigure. The "get" from this is that you would, realistically, have about 1 figure for every 100 parts for MOCs in excess of 200 parts.
In addition, I would say un-empirically, that at least 1/3 of the figs (rounding down) in any set are non-iconic characters..."minions" if you will or iconic but very common figures. Lego does a great job making each figure interesting and desirable but it fills in "minions" to flush out a set. If you have two icon star wars figs then there will usually be at least one droid or common clone trooper. For Ninjago these are Snake units. In Pirate of the Caribbean it was the Gunner and Yeoman Zombies.
In the IP related sets they tend to have at least one iconic character that is very common. Harry Potter and Batman are great examples. These guys are actually the common figures, of their lines. So, even though the forbidden forest (4865) has four named figs, It has one that is very common, Harry Potter, and one that is relatively common Haggrid, leaving Voldement and Narcissa as the rare minifigs. There are, of course, exceptions to this, the latest Millennium Falcon has nearly every major Star Wars character. The realistic approach though is to build towards standards rather than towards exceptions.
I hope this, very brief, article can shed some light on proper minifig distribution.
Previous Cuusoo Analytics: Days Until Review
By the Way, Crvanoorman's Mos Espa Quarters is not only a great MOC but is also a fine example of realistic Figure count for a Lego set.
Anakin's Mos Espa Quarters