I think you'll find that typical adventure design principles may run into issues, in that Warlocks are not really geared for utility/buff casting, and very quickly have to fall back on cantrips.
Moreover, I think the theme might not turn out as powerful as you might think. The Warlock's cool comes from the basic setup that most people do "acceptable" stuff, but the warlock chooses to do something outside the norm, and often of questionable wisdom, to get power.
But, if that becomes normal, where there's a warlock on every block, that's less cool. If everyone is edgy, the window of what seems edgy shifts to suit.
It also has societal implications that ought to be considered. If you've made a pact with some other being, that implies that being has an agenda they are going to push through you. Now you have potentially a lot of these beigns pushing agendas more directly than gods typically do with their clerics. The implications for society and politics are substantial.
Moreover, I think the theme might not turn out as powerful as you might think. The Warlock's cool comes from the basic setup that most people do "acceptable" stuff, but the warlock chooses to do something outside the norm, and often of questionable wisdom, to get power.
But, if that becomes normal, where there's a warlock on every block, that's less cool. If everyone is edgy, the window of what seems edgy shifts to suit.
It also has societal implications that ought to be considered. If you've made a pact with some other being, that implies that being has an agenda they are going to push through you. Now you have potentially a lot of these beigns pushing agendas more directly than gods typically do with their clerics. The implications for society and politics are substantial.