One of the reasons the warlock is in practice the simplest spellcaster is that Eldritch Blast is so strong. This means that "I cast Eldritch Blast" is never a wrong choice, and allows the warlock's spell list and spell slots to be kept lean. What's needed is for each warlock subclass to gain its own at will option. A choice between "I eldritch blast" and "I breathe fire" is far more interesting while not changing the power level much.I actually wonder how WotC would "smooth over" the warlock, given their current design philosophy of emphasizing simplicity and PC power. The easiest way is to reduce the power of Eldritch Blast, but I don't think that would go over well with the fanbase they're trying to court. Maybe make all their options just as strong?
So the warlock now has two primary at wills. Y'know, the way 4e did it