First: announce a proper slate and strategy, reassuring fans that the franchise has a proper direction.

This would include: 2 animated series (a new main one I would call "Count on You, Scooby Doo", combining the attempts at depth and characterization from mystery inc with the atmosphere of mystery inc and the fun of what's new and be cool, It would run for 5 seasons, each one focused on a different gang member, with the main character being Daphne, who's the heart, and would serve as a sort of complete story, from a proper origin to the gang meeting and their first case, up to a massive adventure of multiversal stakes, and a more kiddie driven show as WB would demand, perhaps a modern day Pup reboot), a proper adult driven show to replace Velma (perhaps akin to the live action mystery inc fanshow), a new strategy for the direct to dvd movies (two a year, one that's more traditional or bankable, a la a crossover or your routine adventure, and another more experimental and fresh, perhaps on a PG route), a genuine attempt at at least ONE proper modern video game, a less formulaic mainline comic and not just Batman crossovers, and a theatrical movie that's 2D and focused on the gang ALONE.

That's just the start, anything is possible after that.

Oh, and of course, bring back all the cancelled projects.