Eldritch Strike: It does more damage than eldritch blast, hits a different defense, slides things, works better with leaders, and you already have a ranged attack in the form of your other at will. And doesn't burn a feat, and can do pretty silly damage (for a Goliath Warlock) at level 1). So better all 'round, really.
Draco: obviously, if you've switched to staff tricks, the numbers change a lot, that was why I went "-if- you stick with eldritch strike after switching to staff/staff fighting in paragon". Also, Staff does d8 (which is still less than d10, yes, but not less than 10 +3 prof vs AC). Actually...Strike is still more damage if you consider range/melee a wash with a staff (given that you have another ranged option, and are weaplamenting anyway). +2 prof vs AC a reflex attack is a wash, sure -- but the abilitiy to flank and charge makes a -huge- difference to your effective damage; more, (given that the forced movement can also get you out of melee) than you get from another ranged option vs reflex.
Whether it is, taken in isolation, on par or not with other class's at-wills does not, in fact, make it necessarily the automatic pick for all warlocks. Each warlock has issues that make it desirable or not, because each warlock has a different playstyle.
To put it another way:
Eldritch Blast is the equivalent to "I make a basic attack with my longbow"; a pure replacement sop to warlocks for not otherwise having a ranged basic. It's junk -- but if you can't wield a decent weapon anyway, it's probably worth it, particularly for non-infernallocks.
By contrast, Eldritch Strike is among the top 10 melee at wills in the game. Yes, Twin Strike and Righeous Brand and Magic Weapon are better. But Overwhelming Strike, Footwork Lure, Tide of Iron? All strictly worse, and doubly so (more limited, not a basic attack). So if it fits into your build, it's almost certainly worth taking.
Well, yes.Alright, going over this again.
d8 vs AC (+2 prof) is not a wash with d10 vs Reflex. That's less damage.
Oh, absolutely (though Goliath monks only have Str re monk stats). In general, GWP is strong for implement users that can use a GWP-type as an implement -- I picked warlock because it was the only class I could think of that could get a GWP as an implement -and- had Str or Con as an attack stat.
1. Goliath Warlock at heroic levels: Should clearly take Eldritch Strike -- because she's not going to be hitting with a staff; she's going to be closing in and taking out foes with a greatsword or falchion. After all, that's pretty clear the primary reason to play Goliath warlock, and +3 2d4hc or +3 d10 melee -is- more damage than 1d10 vs reflex no matter how you slice it.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.