Your philosophies and ideas about character amount in film/series/game.

When discussing this, one point you have to talk about is whether you're meaning actual main characters, or just supporting cast.

As you brought up Lost, while there are a lot of characters in that show, about half are just characteratures with perhaps one to two actual backstory episodes. You have a core of Jack, John, Kate, Sawyer, who each have 5+ backstory episodes. For these people we know a lot of personal quirks, we can reasonably predict how they'll respond to new challenges, and we start to feel like we really know them.

Beyond that, you begin to get into varying levels of exploration. Hugo, Sayid, Jin, & Sun would probably be the next tier, as they've all been in every episode, but have a bit less development. These folks begin to become cutouts of actual people, as their actions / purpose in the show are driven by a single concept, but have been in enough episodes that we've learned minor quirks anyhow.

Then you rapidly drop into folks which represent ideas, but don't have a full development. Clair, Charlie, Ben, & Juliet all might be examples of this. Claire in particular is a good example, as she generally just appears whenever you want someone to ask a naive question or bring up family context.

On my personal preference.

As Timber noted, in a normal movie length, there isn't much time to actually develop more than a couple people well. I often tend to dislike focused character studies, like Taxi Driver or Magnolia. That said, its not a hard and fast rule, as some like Fight Club, Lost in Translation, and American Beauty are within my favorite movies.

Generally, I'd say that making a movie with limited main's intensifies the reaction to a film. Its heavily carried by the personal connection to / interest in them. If done well, or using interesting main's, it can often be a greater success with individuals, but this polarization means its tougher to guarantee the reception with a wide audience.

A good example of this is Napoleon Dynamite, which is regarded as one of the most polarizing movies that exists. If people associate with the quirky comedy, and sympathize with the problems of Napoleon's family, then they often regard it as a classic. However, there is a wide audience which feels no connection to the characters, doesn't feel the comedy, and pans it as trash. It has almost single-handedly halted progress on the Netflix algorithm contest.

Naturally, broader, interaction based films without a strong core of mains will be easier to accept, as you're never focusing on one person all the time. Personal quirks aren't as pronounced and intense like/dislike responses are less likely to result. The main impact of association / sympathy that comes across then is overall influence of the writer themselves, as their voice can accidentally/intentionally speak through all the characters at once. (See all of Guy Ritchie's films) I personally often find these movies fun, but without lasting appeal, as the only broad movie of this type which is in my top ten is Lord of the Rings, and with 12 hours (plus books) they have plenty of space to properly characterize all of the Fellowship.

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