With an Agonizing Eldritch Blast, you deal pretty much the same damage as an archer would. While you do not have access to sharpshooter, proper use of Hex should get you very close, especially considering that Hex is "free" to use (no need to sacrifice accuracy, it's just free damage ...
On average, this build does roughly ~64 damage per attack sequence with his Pact Weapon while the Eldritch Blast with all of the damage increasing invocations tops out at ~56 damage. Although a big part of this superiority is dependent on choosing a weapon that deals 2d6 damage (hence greats...
With War Caster, you can provide the somatic components of eldritch blast even if your hands are full of weapons. With Improved Pact Weapon, you could provide the material components of a spell using your pact weapon as your focus, but eldritch blast doesn't have material...