maybe, since there would literally be millions of flavours of warlock walking around, there would be some variants. i tend to think of the "standard" warlock as having eldritch blast primarily because his or her patron wishes to arm his new loyal friend, and keep him alive and well. i realize removing the eldritch blast would severely cramp the style of the class, but perhaps some people, in some areas would develop alternative methods of dealing with infernal/fey energy that aren't always "melt your face off"? i tend to think of construction and sanitation worker wizards in more advanced societies; they probably wouldn't really have magic missile filling their 1st level slots, but would instead have several low level spells required to make life easier, or keep society functioning. things like "power mechanical device", "repair building foundation" and "detect tax frauds"
also, you may want to examine how exactly an entire society became warlock-ish. perhaps, you could claim that a terrible battle between the forces of devils and demons, both intent on claiming this world, saw both sides ultimately annihilated? their raw primal power seeped into the lands and people that lived in them and slowly awakened again. maybe as a twist, this war happened several thousand years prior to most civilizations, so most people have absolutely no idea where their neato powers and abilities really came from?
ironically, i was speaking with my girlfriend about a very similar topic. except, in my proposal, i felt that the typical low-class NPC characters, like the baker, butcher or innkeeper, each had a single least invocation. whereas PCs and more "notable" folk (re: villians) all had a free level of warlock. this came to symbolize that the warlock's "spiritual bloodline" tended to favour the adventuring type who would amass power and fortune, while it merely gave the lessers something neat to make their lives easier. of course, in this situation, the warlock powers were the last remnants of a massively powerful daemon, long since slain and forgotten. i figured that his "spiritual bloodline" still had daemonic tendencies, so it heavily favoured the greedy, powerful and ambitious (classed PCs and villians), but still generally enjoyed being used by hundreds of thousands, so it lent what it could to the 'plebes'.
