When you say, "I think there are others that get even more out of Hexblade" you need to provide specific examples with support. I would love to move this forward, but need more info.
I look at it and think "that's a cool spell".
The signature of champions.
In your level 9 example you could do Hexblade 1, Paladin (Oath of Vengeance) 5, Sorcerer (Dragon) 3. Stat array would be 10/14/15/8/10/18 (variant human). Your feats would be Warcaster and +2 Cha. AC would be 18 with a breastplate and a shield. With Hexblade's Curse and Vow of Emnity your crit chance would be 34% per round (2 attacks). Those crits do 6d8+6 damage with a level 1 spell slot smite.
Please note you can switch out Eldritch invocations as you gain warlock levels, you'd just have a level without 2 attacks
I know you're really happy with Hexblade and College of Blades, but I think there's even more synergy with a Hexblade and a Battlemaster.
Battlemaster abilities (mostly) don't require the use of bonus actions and reactions that the Hexblade loves to use for spells/class abilities, and can add attack, damage, and effect bonuses to the attack, and recharge at the same rate that the Warlock abilities do.
The example I was referring to was the one in Post#121.
In theory, I think to make optimal use of a Hexblade dip is to try to capitalise on Hexblade's Curse's increased crit range as much as possible. So extra dice is the way to go imho. Paladin and Sorcerer both provide those dice (my example looked at a Paladin).
In your level 9 example you could do Hexblade 1, Paladin (Oath of Vengeance) 5, Sorcerer (Dragon) 3. Stat array would be 10/14/15/8/10/18 (variant human).
Your feats would be Warcaster and +2 Cha. AC would be 18 with a breastplate and a shield. With Hexblade's Curse and Vow of Emnity your crit chance would be 34% per round (2 attacks). Those crits do 6d8+6 damage with a level 1 spell slot smite.
It sounds like cool spell, but the implementation, like its mechanical predecessor Witch Bolt, is really weak sauce. Your spending a valuable fifth level spell slot to hit someone within range with mediocre (for the level) damage and a negligible amount of healing for yourself (if they fail the save). This generally means that you want the spell to last as long as possible to "get your money's worth out of it", so to speak, with more damage and healing each round. The problem is that this costs not only your concentration, but your action as well; in addition to the fact that the target can move out of range or behind full cover. One or two of these restrictions might be okay for some circumstances, but IME, this is rarely, if ever, worth it except as a flavorful torture method on a helpless opponent/sacrifice by the big bad. I mean, if you need the healing that badly and don't have a cleric/druid/paladin/bard/First Aid, I guess. But unless you are fighting mooks, this seems like a delay tactic at best, and you would be better served by a "Get out of Dodge" type of spell.