The wiki you have linked to contains the most complete (English-language) list of unique named FO4 raiders online thus far.
The Raiders category page and the Raiders article page both show a list of notable named raiders. Clicking on each raider's name brings you to a page showing the location of said raider. A few more named FO4 raiders appear on the Gamepedia Wiki's Raiders article page.
The rest of the raider group doesn't appear to disperse or aggro when the leader is killed. The named raiders do seem to be a bit stronger than your standard raider, often taking a number of headshots or an otherwise extended firefight/brawl to kill. In addition to being sometimes involved with quests, they also occasionally have keys, passwords, or rare weapons and armor on their person. It's usually worth it to take them down if you have the patience.
As to their importance, one might also ask a different question; why don't most of the other raiders have names? The regular raiders differ little in appearance, equipment, and tactics. Giving them all names might dissuade gamers of any skill level from even attacking the raiders, perhaps judging them all to be important somehow. Meanwhile, players encountering difficulty with a certain section of the game may be able to use the named raider as a descriptive landmark. If all raiders had names, the leader's name would get lost in the crowd. As it is, the leader stands out from the crowd and this lets the player infer that this raider is not to be taken lightly.