Rocky Express was not a popular ride. It never had a queue. It would very rarely have a full cycle. The only time people really paid any attention to it was when it was rumoured to not be returning.
Don't get me wrong, Rocky Express and rides like it are fun and enjoyable. But it simply wasn't popular at Thorpe.
Comparing it to Seastorm, a ride which is in a park with less thrill rides and has a completely different target market, doesn't show how popular Rocky is or would be.
Whilst it may look in immaculate condition, it isn't. The simple fact of the matter is the ride was turned off on the last operating day of 2021 and left untouched. It's had no winter maintenance (which it would have needed) or any engineering checks. And the longer it is left, the worse condition it will get in from a mechanical standpoint. The reason it has been untouched is because there's no need to touch it yet. It's not returning, or being sold or moving on, so they only need to physically remove when it's time to.
There certainly feels like a chance the current plans could be rejected. But whatever happens with the roller coaster project, Rocky will not return, for the reasons listed above.
If the current Project Exodus plans are rejected, it's likely that the park wouldn't be able to build any coaster there (not impossible, but I don't see it happening). I wouldn't say no to Thorpe building a Maurer spinner (or indeed, any spinner...Mack Xtreme Spinner for example), but it would need a much higher throughput than Spinball at Towers to cope with the demand it would no doubt get.
I agree Thorpe could do with more family / family-thrill rides. But a coaster like that at Chessington (a launched wingrider) is very low down on that list for Thorpe imo