I try not to take the lazy option. Personally, I think that hacking an existing game is like writing fan fiction...not bad if you can't write something original for yourself, or can't be bothered developing a whole new mythology and setting, but it's not really a stretch of creative muscles. Hacking a system is like a writer's exercise before the real work begins.
I prefer pulling bits and pieces from various existing systems, and welding them into a unified whole....not a hodge podge of random components flung together (I've had rants on that before), but more like an engineer pulling the engine block from one car, fitting it to the chassis of another, attaching a custom built superstructure, then making sure all the wiring, fuel lines, and other details fit together. I could be building a dune buggy, a hot-rod, a race car, or something else entirely... I'm not just repainting a factory built model and calling it something different. Don't get me wrong, some people do awesome paint jobs on their projects...but it's not really getting into the full potential of design.
One of the things I really liked about later incarnations of the "Vampire: the Masquerade" rules were the possible powers that developed when you combined disciplines. Such things were exclusive secrets of specific societies and groups. It's something I've been thinking about for this game.
I've already specified that I like the idea of a race, a culture and an occupation for characters. It's the kind of idea that's gaining traction through the new edition of D&D (where you have races, classes, and backgrounds).
That sounds like some very different ideas, but bear with me.
I also like the idea of rapid character generation through templates. Pick a race, pick a template variation based on that race...then do the same for culture, and occupation...There's your base character. You might have to spend a couple of destiny points to get the exact combination that you're after, and you might spend a couple of extra destiny points to beef up a few stats, gain a few extra skills or abilities (specifically related to the templates you've chosen), or maybe gain some gold to fit out your character with variant equipment.
The basic idea is that each character is made up of 3 template fragments, and each of these template fragments offers three or four core ability paths with a simple progression (basic, intermediate, expert). A template offers a starting level in two of these paths. In total you'd be looking at maybe 20 of these core ability paths. Easy enough for most people to generally remember which path does what.
The trick comes from combining these paths, combining a "survival" path with a "medicine" path might open up a possible "herbalism" ability...maybe combining an "alchemist" path with a "crafting" path might open up a "enchantment" ability, as long as the character has proven themselves to the School of Enchanters.
How many of these quirky abilities should there be? If there are 20 core paths, should there be 40, 60, 100????
Maybe we create some basic system that allows players to create their own special abilities that can be taught to others. This gives a quick an easy system to get things started, but allows a huge variety and potential for development as the character explores the world and learns from the people around them.
Should there be obscure paths that open up when characters have mastered core paths?
Lots more to think about.