You can play around with mutation rates, zombie and item spawn rates, adding or removing stuff via mods, self-imposed challenge playthroughs, and so forth, but I think fundamentally you're always on that curve: all you can do is tweak the steepness of the slope. At least when I play, the game always has the same basic structure:
Stage one:
- find clothes/armor and weapon
- find water
- find food, medicine
- find somewhere safe to rest
- if necessary, escape initial predicament (lab, prison, etc.)
Stage two:
- set up camp, possibly short term or possibly long term
- stockpile food, water, medicine and/or ways to get those things (fishing, convenient water source, etc.)
- start collecting resources for crafting , tools, and books
- initial forays into the world to gather necessary-for-survival items
Stage three:
- begin scouring the map for missing books and tools, including specialty crafting tools
- learn martial arts, magic if available, work on mutations/bionics if applicable
- start grinding skills
- find a suitable vehicle and modify it to suit my needs
- figure out where to set up a permanent base of operations
Stage four:
- make sure I have access to a wide range of weapons - melee to long range sniping - and good skills
- make sure I have access to armor/environmental protection suitable to almost any situation
- achieve whatever post-threshold mutation I'm looking for, if possible
Stage five:
- raid difficult locations, sometimes recklessly
- attempt self imposed challenges (use only pistols and axes, wear only jeans & a tshirt, collect lots of obscure books or firearms)
- get bored, abandon the playthrough
I find that somewhere around mid-stage four is where the fun starts to peter out, and that a lot of my deaths tend to either happen in stage one or early two, or else stage five. Early stage one can get to be a slog, if only because you die a lot, but there's a definite moment sometime mid-stage one - usually when you get a good weapon, or lucky with an early good armor or martial art - that you go from being prey to being a predator, at least as far as lone regular zeds are concerned, and that's where it starts to get fun.
The Cata devs (both DDA, BN and other forks) are all aware of this, and in some ways a lot of the shit that Kevin & co are doing with skill specialties and all that other nonsense are fundamentally about making it take longer to climb up that curve. Yes, they are prolonging the "fun" part of the game, but they're doing it in some incredibly un-fun ways that just add tedium. Ultimately, though, this fundamental structure can't be changed without making the game something fundamentally different: Cataclysm as constituted is always going to be a game where your choices are either A) become more powerful, or B) die, and as long as you can become more powerful, you will climb that curve.
Edit: Ah, fuck, now I want to start a new BN playthrough. Haven't fucked with it since August, and one of the nice things about checking in on a game like Cata once or twice a year is that there's always something new and surprising when you do.