The OGL and the farming out of module creation is one of the worst sins WotC did. The focus of the game went from the iconic shared adventure to the splat rules bloat. It shaped 3.5 and 4E into the encounter format. 4E did not spawn that 3.5 releases became very formulaic. There were some great 3rd party mods, but there were a tremendous amount of really bad mods produced.
Paizo success stems from excellent editing and a wide net for authors. The Adventure path was novel but is just a railroaded campaign. I would like to see looser connected adventures or shorter paths.
Dungeon needs to return to a submission based magazine with rock solid editing. WotC needs to release adventures to keep their design and development grounded in what the game is about, the 3 pillars, combat, social, and exploration.
I want to see evocative settings like The Kingdom of the Ghouls or The Styes. I want to see adventures that require problem solving and not the Gordian knot cutting of All combat, All the Time. I want to see combat encounters that feel epic and challenging with options for innovation. I want to see great adventures to be in the lexicon of D&D players again.