While I don't like the current gas system on AR's/M4, I am not convinced that a bolt on gas piston system is materially better.
One guy reported having slamfires with winchester factory ammunition. That extra weight added to the carrier increased forward momentum. The soft WSR primer was going off as soon as the firing pin bounced off it.
If the weapon system was being designed new, I would go with a gas piston. But modifying an existing design, I don't know. Bolt on's, adapters, etc, they have not seen as much field use or development testing as the existing system. Could be the cure, could be a problem.
The current AR system is mechanically reliable, and if kept clean, will function adequately. It is more maintenance heavy than other designs, but just clean your rifle after you fire it and lube the heck out of it.