Well Agonizing Blast is a must as it is and then I took Repelling Blast, which works very well. IMO, with what we have now with only one short rest and what amounts to 3/4 of Warlock implementation and level 4 cap - really need to put all the eggs into Eldritch Blast, there is just no space for nonsense invocations now. All more considering Wizard is freakishly powerful with its silly surface spawning cantrips that are on par with Eldritch Blast at this level if not stronger actually.
At least Warlock has Dark One's Own Blessing, which is really powerful at that level too, but when it comes to gunning things down - Wizard is just much stronger at level 4.
