I think I understand the question - Who are the guys who could fire in balls the most accurately from distance or at severe angles. This is irrespective of their overall ability to run racks or play position of any of the other attributes of great players.
The straightest shooters I ever saw in my lifetime begins (and ends) with Louie Roberts. He was supernatural at making shots from all over the table and hitting them into center pocket! He could have played on 3" pockets and done okay. Louie could fire those balls in like they were hangers and bring his opponents to their knees. I never saw anyone cut balls down the rail quite like him, like they were on a string leading directly into the pocket, never touching the rail all the way in. None like him before or since.
After Louie, I would rate Richie Florence, another ball making machine from my era who would frequently run out without ever getting good position on any ball. And I must give a nod to Lou Butera who was well known for his rapid fire play, but was also deadly accurate from anywhere on the table.
In more modern times the first player who comes to mind is John Schmidt and then Jayson Shaw for the ease in which they could pocket the most difficult shots. Then there is the amazing Joshua Fuller who makes EVERYTHING look so simple that you don't realize how hard some of the shots are that he is stroking in so nonchalantly.
Yes, Buddy and Sigel and Parica and Earl were all great shotmakers but their excellent cue ball control made that less of a problem for them. They rarely were forced to shoot a tough shot, other than when their opponent left them one. And the guy who many of us think was the best of them all, Harold Worst, could make any shot imaginable but once again he handled the cue ball so expertly he rarely had to. As for Mosconi, he was ALWAYS close to the ball! Lassiter played kind of like Buddy, who saw him as a mentor. Position, position, position was the name of their game, and playing all the right angles/patterns was what worked for both of them. I left out Greg Stevens who was also a great shotmaker. He was usually enhanced though.
My last word - If there ever was a shot making competition and all these guys were in their prime, Louie would crush them all!