I am glad that this thread has been put up, as I enjoyed reading all the various comments about Nemesis: Sub Terra, as well as the various ways it could be improved (e.g. varied ride sequences, integrating it more with Nemesis in a baby-parent bond way, so Sub Terra is the precursor to the great rollercoaster).
Personally, my biggest problem with Sub-Terra is the Nemesis branding, because I think it would've been better it if Sub-Terra was a ride in its own right, rather than a spin off of an AT classic. The branding has to some extent put me off riding it, because Nemesis is my favourite ride in the park and I personally don't want to risk it being tarnished by a relatively poor spin off. That's just my opinion and I know many others won't share it, which I fully respect.
I totally agree that a new ride needed to be placed there. My best friend says it should've been Dynamo, completely revamped mechanically so it doesn't breakdown (to this day he mourns its departure). I would've like to seen a dark spinning drop ride where there is a central point with three arms, which spins. Then attached to the three arms are three or four smaller arms which carry the gondola, which also spin. But as well as that, every so often the mini-arms drop the gondola while spinning and the gondolas drop at different times from the others. Because the ride is in the dark, the riders don't know where they are going, but feel they are moving in three or four directions at once. This ride would be called Sub-Terra, as it would reside in a man made hill and it would pay tribute to Dynamo and Black Hole, as well as ride idea of Nemesis: Sub-Terra. I would've certainly gone on it, even though I know it would make me feel sick!
I would then tweak the Forbidden Valley theme, by making it an area themed around the elements. The backstory could be something like how this group of people (maybe the phlanax) went mad and obsessed about experiments on the classic elements and more. I would then refurbish the rides, especially the flats and designate the following: The Blade- Fire (complete with burning fire braziers), Ripsaw- Water (complete with new water cannons attached to the side of new spinning saw discs), Nemesis- Earth (I'd keep its own theme) and Air. Sub-Terra would be themed around the Darkness. Each of the rides would have speed in common.
If I had the money, I would then move The Blade to the side (perhaps closer to Ripsaw) and then bring back the Thunder Looper (albeit quieter and lower in the ground) and theme it around the culminating "Final Experiment!" Then you would have SIX decent rides in one area.
That's what I would do to Forbidden Valley.
Anyway, I do respect the ideas behind N:ST and the theming and I understand why people like it and go back on. From what I've seen, read and heard, there are elements of it that are good- such as the ride itself. But as I say, I think it would've been better had Alton Towers built a dark flat ride, with its own theme but still blended in with the theme of Forbidden Valley. This way it would have avoided the publicity hike which increased the let down factor for many riders (because of the links with Nemesis).
Aside from the links with Nemesis, there are other reasons why I have no desire to go on it. Personally I am not a fan of things jumping out at me, there's nothing that's persuading me to go on it (unlike The Smiler or Thirteen) and I have no desire in being shouted at or pushed violently by thugs with guns lol! I'd just shout back "I'm going nowhere near the contamination area! However I will go to the 1994 site and nothing you can do will stop me!!!" I would avoid Phlanax like the plague, because they don't look like the sort of people you can trust. Perhaps that's the irony, they are your nemesis. I would certainly love to see the that organisation meet its retribution for all the things it has done (btw Nemesis is the Goddess of Retribution in mythology).
So in my opinion, Nemesis: Sub Terra will continue to operate for another few years and then if there is a poor throughput, then it'll either be rethemed to just Sub Terra, or new name or at the very worst removed completely. Eitherway, I won't be going on it for the reasons mentioned above, but I won't stop others from doing so.
Sorry for the long post, but I felt I had to air my views in as balanced a way as possible.