The story is that Honda went back and forth, trying to decide if the GW was going to be their next superbike, or more of a dedicated tourer. The first-gen (75-77) bikes are the hottest, and with each generation after that they de-emphasized HP and pumped up the torque (weaker cam, smaller carbs, lower compression, etc.).
The most obvious tuning weakness of the first-gen bikes is a pronounced stumble off of idle. The solution is to make the air bleeds smaller to richen the mixture. The '76 GW "LTD" had the smoothest tuning from the factory.
Check out randakks.com for this and numberless other tips, tricks, and parts for these remarkable bikes of all generations. Randall Washington is one of the prime innovators in GW technology. He's built supercharged and Weber-carbed versions from scratch over the decades.