So, no one asked for this novel, but you've touched on a special interest of mine and now you will pay:
The image/presence of Durga(**) was not specifically copywritten, nor was the concept of icy stalactites, nor was the idea of a lava pit.
The entire concept of a ride like Tomb Raider: The Ride was patented to Paramount Parks, Inc. You can see the patent here: link. (It's got some cool pictures I geek out pretty hard over.)
Included in the patent are the following descriptions, paraphrased:
A HUSS Giant Top Spin ride (or similar product with at least three rows of theatrical seating) synchronized with theatrical effects, including music, lighting effects, audio, fog, fire, water, smoke, and/or steam
Using said ride to stop riders at a number of predetermined locations in sync with music, lighting, audio, etc.
Seated-integrated loose article receptacles, such as a bag
An exact description of the TRTR ride cycle, including the locations of the gondola, descriptions of when the gondola was meant to lock and unlock, and which effects were meant to trigger at each location
A description of the antechamber (the room before the preshow) that contains specifically named items like stone archways and the stone monkey statues that were used during the filming of Lara Croft: Tomb Raider (2001), as well as the presence of fog in the room
A description of the preshow room that names specific actions like the antechamber door closing behind guests (including accompanying sound effects), the faux fire lamps, the use of the preshow screen, and of course the audio and video of the preshow itself
The door itself between the preshow room and the ride chamber (##)
The headlights on the front of the gondola
The jewels in Durga's (**) hands and the fact that they are backlit, as well as the lasers in Durga's eyes that scan the gondola
Blacklight effects in the ride chamber (##), period
The aforementioned razor sharp ice spikes and their use of mist, dripping water, and fiber-optic lights
The volcano and its use of mist, water, lighting, and fire (the last of which was never part of the ride experience, to my knowledge, but can you imagine?!)
Admittedly, that link DOES say that the process of patenting the ride was abandoned as of 1/10/2005. I don't know how or where to go to corroborate that date or discover whether or not it would have given Paramount additional legal standing to sue if Cedar Fair had been less heavy-handed with the retheme. I'm also under the impression that Cedar Fair absorbed Paramount Parks, Inc., so one could assume that ownership of the patent would have passed to Cedar Fair if it still had any legal merit.
If the patent wasn't the reason for the heavy-handed retheme, then it was almost certainly overcautious lawyers and Kinzel-era "thrills first" thinking of the time. Note that short of the loose article bags and the preshow-ride chamber door, none of the things I pointed out from the patent remained when The Crypt opened in 2008--not even the presence of a third row on the gondola. It got reduced down to two rows beginning in 2008.
Even then, though, if you ignore the patent, that ride was of course chock-full of references to Lara Croft: Tomb Raider, which remains Paramount-trademarked film. These references included but were not limited to:
The Triangle of Light (a magical artifact from the film) in the queue, antechamber, and ride chamber
Queue music that sampled the film score and ride audio that sampled film dialogue
Monkey statues that were used in filming
A preshow room whose decor was an in-spirit recreation of the Cambodian temple scene in the film, including the Brahman statue behind the preshow screen
A preshow film that used audio and video from the film
If you take those away... there's not much left to work with. There's more than what The Crypt operated with, sure, but you've taken a lot away from the experience. It's not inconceivable that Kinzel-era CF saw what remained and decided to ditch the theming (which was never their forte, and Paramount hadn't exactly kept up with what was there) and go for thrills, which is definitely what the first 1.5 years of The Crypt had to offer.
Curiously, Kings Dominion's Tomb Raider: Firefall/The Crypt stayed almost intact throughout its life and only lost its one reference to the Triangle of Light. It straight up kept its monkey statues AND audio references to the Lara Croft: Tomb Raider film score. Which makes me think all the more that Kings Island's drastic de-theming was more because of the patent than anything else. Kings Dominion's ride was not patented and (in my non-lawyer-y opinion) did not match the description of the KI ride's patent. But, that's just my guess!
** = It should be noted that the patent itself claims the god represented in the ride chamber is Shiva. Over the years of being curious, I've never found a depiction of Shiva or Durga (or any other Hindu deity) that seemed conclusive enough to say. Either way, presenting a deity of a real-world religion as the antagonist of a theme park ride is... a choice, and perhaps a product of its time that wouldn't and shouldn't be repeated today.
## = I do love that the patent refers to the ride chamber as the Heart of the Tomb. That's a cool name.