Note: As with previous [Minis+] threads, I will ask that any participants accept as a given that we'll be talking about minis use in a positive way. A core assumption is that you dig minis-use, you like them as toys as well as (or more than) as markers, and that if you aren't a minis using, you'll still be welcome to participate, but with the understanding we'll be looking for positive suggestions. Also, our look is at least a bit more for "dirty-hippy"/story game approaches, rather than the more classic, wargames type approaches, even if moving and playing with the toys is an expected part of the thing.( I have access to about a millionzillion wargame approaches already).
Okay, so there have been lots of these threads and I've gotten some great feedback and suggestions. I've seen a few broad types of approach, and I wanted to pull them together here. I'll ask the folks who originally posted stuff related to these to forgive me if what I describe next doesn't fully convey the nuances. My categories are based on my take-aways from those posts, not necessarily the original posters' points.
The minis rollercoaster adventure ( aka Eero's Sipi game)
As I understand this approach, it's a bit like a more traditional voluntary rollercoaster. Eero states this upfront to his players and gets their buy-in first. The adventure designer/GM has distinct locations in mind, a broad outline of the sequence of events, and motivations for the NPCs. I'm guessing there's a good bit of leeway for exactly how things turn out, based on what the characters do during the course of events, but it's still largely a river flowing in one general direction.
Creativity of players and constraints at the start of play
Players have a pool of miniatures to choose from to make their characters, but a major constraint is that any character must in some way be a friend/minion/employee generally loyal to and attached to an NPC ( Sipi, a rogue who gets them into adventures and trouble. Sipi is the hook and the tie that binds them together). Eero reported that players who chose weirder looking characters made a point of emphasizing the obvious, visual and physical characteristics when building the characters based on them, while players who chose more general miniatures used them as a more blank canvas. Character creation was broad and general, verbal descriptions perhaps with some quick notes, although some mechanics existed to describe a handful of characteristics that had some mechanics paired with them.
The other major constraint Eero used was a "genre" one: It was understood from the outset that play was based on the feel of fairytale style stories.
Players had a lot of freedom to portray their character and develop personality through interaction. Base mechanics used were broad, and, in keeping with both dirty hippy leanings and Fairy Tale feel, success or failure of the characters was based more on player level rules than an attempt to create hard measures of capability and compare them in some fashion.
Characters went through a series of scenes at locations, based on the GM's preplanned concept. Locations were limited to prepared spots, although my impression is that the order that those location+scene combos took place in was somewhat flexible based on players' actions with their characters. The broadly planned sequence was maintained, however.
Thoughts on the advantages of this approach
While Eero mentioned there was a great deal of prep work for this, that may be partially because Eero was staring from almost scratch with this style of play! OTOH, there was also a fair bit of prep that needed to be done by the GM in terms of thinking about that sequence of scenes, mapping/drawing the locations and having them ready, and coming up with the broad story and NPCs.
On the upside, this seems from his description to be a great approach when you have a limited pool of miniatures and limited space. Eero largely stuck with 2-D environments, iirc, and of limited size. With this approach, a group using the usual "play RPGs at a kitchen table of modest size" can easily do this sort of thing. 2D maps/drawings of locations are fairly easy to transport and to swap out, in a way that 3D terrain is not.
Having noted that things were going to be a rollercoaster storywise ( the positive version of a railroad!), players could be a bit more focused, less meandering, and put their creative energy into portraying the characters and showing their creativity in those areas ( for the fun and amusement of all the participants).
With that core set up and some locations that undoubtedly could get re-use, there's a pretty solid potential for Sipi and his pals to continue on to other adventures. 2D terrain, whether printed out from a commercial pdf or hand drawn, allows for a whole gob of freedom in what that could be, while staying on a decent budget. It may also allow for a slow build of miniatures in an overall collection, dictated by interest on the part of the GM/designer in putting them in future stories.