When I first started my miniature range, I made a set of 4 multi part heroes - a wizard, barbarian, fighter and rogue. Each of them had 3 heads, 3 left arms and 3 right arms. When I came to get them produced, the manufacturing costs were prohibitive because it was based on individual components and mould cavities so I had to pare it back.
I changed to making dynamic posed hero miniatures without the options, that were cast in resin. But these frequently required parts to be removed and keyed to facilitate the moulding process. When I later started selling the STL files, I sold the files cut up like I was using for my resin masters, 3D printing customers were baffled by this and couldn't get their heads around multi part models to the point where many didn't even know what glue to use to fix the bits together. So I went back to doing single piece miniatures and they went down quite well. Later on I found those 4 original minis and decided to release them. They instantly became best sellers and I never once got a complaint about them. So Multi Part models tend to go down better with customers if they have options.
Now some time later I started releasing Level Up Heroes - one body for a Noob, another for a Veteran of the same class, and then finally the Epic version - see the pics for some examples). Each one had a ball socket for the head and at the wrists. I had a whole library of heads and weapon options that were all interchangeable. Each month, I made a male and female of each class along with a bunch of new accessories. These sold well, but were a drain on me trying to design this progressive upgrade and make them all cross compatible. So each month, my output was just these 6 bodies and the various new heads and weapons etc that I was making. (On a tangent, I will probably be returning to these soon to expand the range).
In the same 1 month window, I also made the entire contents of the first image by making myself a modular collection of different leg poses, torso poses, heads, weapons etc, and essentially kitbashing the whole lot. I subsequently spent a few months expanding this group into a full army and released it all as a Kickstarter project that made me over £30k.
The point is, both were made as multi-part kits, but one was for my benefit and the other was for the customisation by the customer. I've not yet tried to do multipart poses yet (i.e. legs separate to torsos, arms etc.) because I find it quite restrictive and planning them out is logistically a bit of a headache! I'd probably be more inclined to do it if I was making a set of models for a game like Mordheim where you have customisable gangs.
I'd be interested to hear your own views on multi part models. Do you love them or hate them, and why? Would you be more inclined to buy a model that has customisation options or is a single piece character the better option for you?
Also, on a massive tangent, I did a bit of a rebrand in the middle of all of these releases pictured, hence the different render styles. I'm considering a return to the black and yellow branding in the future so I'd love to get some opinions on your thoughts on it!