I think a JP theme would be great, if done right. I have no idea where JP IV stands, but if they were to make the movie, then I agree with Flynn in thinking it's a perfect chance for Lego to redeem themsleves.

(I mean in regard to their previous "Jurassic Park" sets.) I think if TLG were to pick up the JP license again, some new molds would have to be in order. I mean, come on... Toothless raptors? That'll be- Sorry, would have been the day...
Having no idea what the new movie would look like should it ever be made, I can't say I have any ideas for sets lego could do there. However, I do have a couple ideas for some sets from the previous films... Actually, knowing me, maybe I'll just stick with the first one...
Isla Nublar Landing:Includes;
1 helicopter, somewhat akin to the Coast Guard Chopper, that can seat 2 pilots, as well as 6 minifig passengers.
2 Jeeps, capable of seating 4.
Landing pad.
A bridge or structure of some sort as a "filler"
Minifigures;
2 chopper pilots
2 drivers (or maybe we could forfeit them and just have one of the main characters drive. Less $$.

)
John Hammond
Ian Malcolm
Donald Gennaro
Alan Grant
Ellie Sattler
Dinosaur(s):
1 Brontosaurus
Price: (here's the kicker)
$79.99
Nedry's escape:Includes;
1 Jeep, including soft top.
1 Sign (for the West Dock)
2 fence pieces (crash-through action!)
1 tree and possibly some foliage
Shaving cream (embryo) can
Minifigures;
Uhh... Dennis Nedry.
Dinosaur(s):
The... Whatever it was. *looks up name* Found it!
1 Dilophosaurus.
Price:
$10.99 (Maybe sacrificing the sign and/or fences)
Jurassic Park:Includes;
Theme park building (with the T. Rex skeleton in it) with open up action, along with a 2-level foyer, the kitchen, and the control room.
2 Ford Explorers (or generic SUVs somewhat akin to them, to avoid licensing an' stuff), able to seat at least 3.
3 Dino paddocks
1 destructible outhouse.
(possibly) a track layout for the trucks to follow, as well as some trees n' such to make it "more interesting".
2 flare pieces.
1 goat.
Minifigures;
Alan Grant
Ian Malcolm
Donald Gennaro
Tim Murphy
Lex Murphy
Ray Arnold
John Hammond
Dennis Nedry
Ellie Sattler
Robert Muldoon(?)
Dinosaurs:
1 Tyrannosaurus
1 Triceratops
2 Raptors
Price: $99.99 (or more like $119.99)
Raptor Hunt:Includes;
Shed (to run towards).
some trees and foliage.
Minifigures;
Robert Muldoon
Ellie Sattler (?)
Dinosaurs;
2 Raptors
Price:
$7.99
So, there you go. Now you see why I decided to stick with just one movie.

I know the prices are unreasonable, but I watered it down as much as I could...