IMO single target damage is generally far superior than a spread out a small amount of damage. All those enemies are still doing full damage when they are down 4-5 hp. Weak AoEs can be borderline useless. (Not to mention the DM headache of tracking 4 damage on these 4 mooks.) If you are actually in a situation where the AoE is productive, the enemies can easily afford the attack to swat the turret down. While it is good to save an attack on a PC, at that point you're spending a spell slot to negate an attack, which is sort of like a shield spell that uses more than your reaction.
The real problem is the action economy. Between hex and moving it, most warlocks don't even have the time to do much more with their bonus action, especially hexblades. Sorlocks tend to only use the quickened EB on an enemy that is really tough, tough enough that it didn't die after your hex, EB, full team turn, EB again... Basically its a NOVA tactic. I know many people dislike NOVA tactics or builds, but they are quite potent. (There is a reason smite builds are so prevalent.) Buying time in D&D, IMO, is almost never a good strategy. You might not spend resources, but the rest of the party probably will. It is in PCs best interest to end combats as quickly as possible with as few resources spent as possible.
All that being said, if the two classes both used the same stat (int or cha), than the whole thing would be a lot more comparable, and would naturally be high rated.
I was thinking celestial warlock is well. Probably a half elf or maybe a variant human for Inspiring Leader. Those free THP go a long way into making you a strong support. Pump cha with ASIs so you can still spam EB for offense. With 3 or more warlock levels you'd grab the petvantge and maybe the max self healing invocation. Although you probably want to put most levels in artificer, so you can hand out items and stuff.
You're not overpowered or anything, just a candy shop of goodies for the team: advantages, THP, healing, a few items, etc..