I wholly agree with you on that first point! The Crypt's building and area would be better suited to a Rivertown expansion so a new lake and town area could be added alongside a new dedicated entertainment venue.
The Vortex plot should be occupied by a thrill coaster — not a family thrill coaster. It doesn't need to be the biggest or baddest of anything, but a Big Bear Mountain-style coaster would not fit what the area does need. Whatever replaces Vortex needs to be photogenic and vertically diverse. Photogenic to give guests a new visually stunning ride to view from the pathways. Vertically diverse so it both adds to Kings Island's skyline while filling out the space provided by the ravine. The park also has a desperate need for an inversion machine, and family coasters very notably do not feature inversions. If the park was looking to make their next coaster family-friendly, why would they use the Vekoma Ghostrider model on the most recent survey?
I understand that Kings Island is a "family park", but those families grow up and want more thrilling coasters as their children get tired of what the park has. There's an argument to be made that it should have a 48" height requirement (or similar). I get why that might be. The issue is that Kings Island has been playing it safe and it has not worked out in their favor very much. Orion was made to appeal to families and didn't receive a high enough ROI: though Orion opened in July during the middle of a global pandemic, so there were other issues with its opening. River Racers was designed to appeal to a larger audience while leaving more budget for other attractions and did not receive very stellar reviews in its first season of operation. My point with these two examples is that appealing to a broader audience hasn't really worked out well for Kings Island. Yes, families who want thrills could go up to Cedar Point, but it's unlikely that they would go as often as they might if they could have something more thrilling at KI. As families struggle more with the economy there's also less chance that they'd be willing to travel the 3+ hours.