Hi /tg/ I'm trying to start on development of a campaign

>>54393498
GURPS.

>>54393498
>>54394122
GURPS is versatile in setting, infinitely so, but not particularly versatile in tone. It's tone is very gritty, simulationist, and low-heroism. That might be what you're looking for.

INterrestingly enough, 4e is also setting neutral, but inflexible in tone, but while GURPS is setting versatile because of all the interchangable subsystems to, 4e is setting versatile because the fluff-crunch separation means you can refluff the classes to anything you like: from space opera archetypes, to giant robots.

However, much like GURPS, it is also inflexible in tone. There are always three universal truths in any universe you are running using 4e.
1: Melee weapons are a viable choice in combat, even if guns exist.
2: Flight is not going to be available in combat before epic tier (I.E. when things start getting... you know... epic)
3: The PC's are the goddamned heroes of whatever story it is you're telling. They are not a band of mercenaries who met in a bar just trying to survive by delving through underground teasure-troves: they are the PROTAGONISTS with a capital P


Honestly.... between GURPS and 4e, you've basically got every setting and tone covered, so the question you have to ask yourself is: do you want your PC's to be the protagonists of the story who are destined to save the world, or vulnerable pieces of a living breathing world that functions with or without them.

If you chose the former, go with 4e. If you want the latter, go with GURPS.

>>54393498
As others have said gurps can handle your idea well. If the system is too "crunchy" for you perhaps try other generic systems like BRP or even the cypher system. If you want something very rules lite maybe Fate, though personally i cant seem to get myself into fate.