The attack cantrips become gold when their specific situations arise (defending/hitting two foes), otherwise they're blue. At 7-10, using them is very good. At 11-16, trading 2d8 for 1d8 or higher + STR/DEX is kind of an even trade, but an extra attack means another chance to hit, too (another foe or the same). From level 17 to 19 it really is better to use them. All of this assuming the EK is taking his two cantrips on melee cantrips (which would reduce melee-ranged versatility) and also using up their bonus action every turn.
Extra attacks smooth out the damage curve and prevent overdamage, but unless I'm squishing kobolds, once I have War Magic I would pretty much always use Booming Blade instead of Attack action. You're either controlling an enemy's movement or you're getting bonus damage, and that's a worthy trade for some spikes in the damage curve.
Yes, it's nice to be able to get those extra attacks if you need to use your bonus action on Second Wind, but the core of my point is that this should be the exception for the EK. Once you have War Magic, melee cantrip is the rule. Although if you surge, you'll probably want to use that extra action on attacks instead of a melee cantrip, since you can only trigger War Magic once.
You're right that an EK should probably grab a ranged cantrip with one of their picks, but they get a third cantrip a few levels after they get War Magic, and as I've been trying to demonstrate, as of level 7 (also level 3 and 4, I guess), Booming Blade alone is almost always going to be better than the Attack action. And if you're multiclassing to another caster, you'll get more cantrip picks, and once you have War Magic, your DPR will keep pace with a pure fighter while you advance as a caster.
Speaking of multiclassing, besides Eldritch Blast (thanks for backing me up on Agonizing Blast zaratan), a warlock multiclass offers all the usual bladelock tricks. Armor of Agathys, Hex, Hellish Rebuke (although yes, EK has no shortage of reaction abilities), Dark One's Blessing, and Darkness + Devil's Sight. At high level, Lifedrinker + War Magic even grants you something equivalent to a 4th attack. You lose out on Haste if you go deep, but warlock multiclass really deserves better than red, IMO.
Alright, time to quibble about spells. This is the only guide I've seen that rates Melf's Acid Arrow over Scorching Ray. The damage just stinks. An upranked Magic Missile does just as much damage with no miss chance and no waiting for a second round. And most casters rank Minute Meteors as perhaps on par with Fireball, but not better. That's because of the smaller area, the longer time it takes to apply damage, and the use of concentration. And you can probably guess by now that I'll also complain it competes with War Magic.