I think the problem with any replacement that isn’t a carbon copy is that, assuming it is stays contained to its footprint, a replacement would lose the only thing that makes Flyers unique… the free-dangling experience. The ride path is extremely simple and experience generally uninteresting, aside from its striking height and uncontrolled swings.
The age restriction was established to address capacity issues (it use to get three-hour waits). The capacity issues occurred because the ride intended to be strictly kid-focused, but inadvertently became popular for adults. Rebuilding it with modern principles (and improved capacity) likely ruins it. At that point, replace it.
But then you run the risk of losing the playground.