How did I never respond to this? I am a dumb, dumb, dumb person, and this does not speak well to my probable success. Anyway, on to answers!
Biggest question seems to be "Do you have any actual ideas, or just a vague fluffy concept?"
The most overarching example is the dice mechanic, which is XdYkZ*. X is a representation of training, Y of natural ability, and Z of general awesomeness which primarily serves to keep the RNG reasonably constrained, along with a cap on Y. You can't do this with a pen and paper game, because it's complicated as fuck (especially Y, since it can result in impossible or improbable die sizes). It's trivial to do it with a random number generator in a program, and it allows you to generate result distributions that are significantly more interesting and (in my opinion) meaningful than, say d20+mod or the White Wolf system.
MUSHes look relevant to my interests. Based on
very brief research, they're significantly more freeform than what I'm interested in producing. Although I don't much mind if people use the game for porn. Entertainment is entertainment, after all, and the design I've got in mind doesn't operate on central servers, anyway. The networking aspect is much more like
Gametable. So, y'know, whatever, it's not like it's going to have an opportunity to rustle my jimmies.
Settingwise, I plan on starting with a magitech/fantasy setting, but the rules are intended to be extractable. The second setting I've got in mind is a far future sci fi sort of thing, where that sort of integration is likely to be exactly the highlight.
Those two websites in that post, Captnq, are actually very similar to my ideal, since I'm hoping to release a program that does what ditzie seems to do, and have the rules hosted on a Wiki with dedicated homebrew and adventure journal sections that will (in my magical fantasy where everything works) form the bulk of content by volume.
I have not seen Dungeon Robber until this very moment. It looks like an extremely useful utility for that style of gameplay. It's on the opposite end of Dungeon Design tools from Dwarf Fortress - it's fast, efficient, and doesn't produce anything that makes sense.
*I have a clearer format in mind for typing these rolls out, but it's tangentially related at best. Don't want to bother getting into it, unless people are interested.