I know, that is one shot and is not in line with their design philosophy to maximize short range kill potential. Original Golden Gun in D1 had combustion, a 6-shot golden gun with Combustion would absolutely be a monster in clearing.

Combustion in D1 was a way to increase the kill potential of Golden Gun beyond three(/four). Outlaw in D2 absolutely doesn't need that because you already have increased kill potential by having more shots than Sharpshooter, and every kill gives you another shot back. Under perfect circumstances the only limit to how many kills you can get is the duration of the super.

While this is true on the unlimited amount of kills getting more bang for your buck (pun unintended) would be a welcome addition and wouldn’t hurt the super in any way