I do have the same feeling that Chessington will rot if (or when) this opens. Although hopefully this won't happen and people will still support the park (I definitely will) But who knows until after this is built.
But I really am excited for this project! I have a feeling it WILL be built. Nimbyism isn't too much of a problem because the area is very industrial and the nearest major settlements (Dartford and Gravesend) are a few miles away. Although Swanscombe (The nearest settlement to the park) is quite close, They has been a lot of development in the area over the past few years (High Speed one, Bluewater shopping centre for example).
This will have more benefits than problems. This park and the area itself becoming successful for these reasons:
1. Bluewater shopping centre (one of the largest in the UK) is close by as well as Lakeside shopping centre on the other side of the river
2. The park is JUST located outside the M25, allows good road access
3. Rail transport is very good, Swanscombe station is near the park (I think?) and is serve by trains from London Bridge, Charing Cross and Cannon Street. Ebbsfleet is served by international trains which allows even easier access.
4. Park is already located very close to London, not to mentioned trains coming in and out of the above mentioned stations have easy connections.
5. This will created 27,000 jobs! Which is something Britain needs badly
6. Will be great for local businesses as well as Bluewater (and most likely Lakeside), bringing in more money for them.
Not to mention that the concept art looks ace as well! Although as Sam said, things could change and we could get a completely different park.
Hopefully this gets built and I can't wait to go if it gets built!