While it doesn't fit with Voldemort's usual sense of arrogance and dramatic flair, it's important to note how the first Horcrux came into being.
The very first Horcrux made by Tom Riddle was Tom Riddle's Diary. It was most likely created in 1943 immediately after the death of Myrtle Warren, which was caused by Tom Riddle ordering the Basilisk in the Chamber of Secrets to stare into her eyes, thereby killing her.
It is safe to assume that he killed her not specifically to create a horcrux, but rather because she would have been a witness to his opening of the chamber and practice of Parseltongue. However, this act still split his soul and in that moment, Riddle decided to take the opportunity and place that soul fragment into the diary. Since Myrtle wasn't anyone particularly special in Riddle's eyes, there was no sense making sure that the remaining 6 kills were people he considered important to him, because the pattern would be incomplete and the "Power of 7" wouldn't apply.
As such, it freed him to simply kill whoever happened to be nearby whenever he wanted to make a Horcrux. All that mattered was that the object his soul was placed into was important, not who he killed. One could argue that had Myrtle not been in the bathrooms that day, Voldemort may well have attempted such a pattern of "importance" and as a result found it much more difficult to create his perfect set of 7 Horcruxes.