If I were voting, I'd cast my ballot for Michael Estève. He represents the "preservationist" view with regard to what will happen with the old Six Flags property (if and when it sells... and if and when new development starts.)
He has a long record of fighting "sprawl development" and has explicitly campaigned on preserving green and open space. He favors a "livable, lovable, and local" approach that prioritizes existing residents' quality of life over massive new commercial destinations. The "National Harbor" model is not something that would be a good fit for Bowie.
He is the candidate most aligned with your skepticism of "glitzy" deals. Estève has publicly criticized selective developer tax breaks that he believes erode public trust where the promised job-base and infrastructure never materialize. He favors a "neutral arbiter" approach, focusing on businesses that have a proven, sustainable customer base rather than those chasing a temporary "newness" factor.
The "Live!" casino is just 20 miles away... and another 3-star casino (ie, not a tourist destination) would end up with not enough business to sustain either location. A luxury casino, like MGM, is too far "off the beaten path" to attract the "whales" that MGM/National Harbor seek and cater to.
Hopefully, he'll be a strong advocate for a Town Center type of plan... once enacted, it would be easier for a city to hold accountable because it is built in smaller, verifiable phases. It would be mostly self-sufficient rather than relying on tourism. A "resident-led" development would be one that avoids the "glitzy" trap.
But, something like this is always going to be a marathon and not a sprint. Looking at the Landmark Mall demolition and redevelopment as an example for how quickly things might get done, the old Six Flags would be transformed by 2035, maybe.