The ride closed when it did because of cuts following the Smiler incident, the park then clearly enacted a plan over the next 10 years as to how to move forward with future ride investments which included the construction of Wickerman, the TLC for Hex and the retracking of Nemesis, you would hope that it also eventually includes new permanent flat rides which will replace the retro squad.
Given the fact that Nemesis was going to be retracked and out of action for a season and the park only has a finite budget to spend each year, it seems to me that Nemesis Sub Terra’s reopening was always decided to coincide with Nemesis’s retrack.
The idea that the park would leave a ride SBNO for 8 years which would have presumably required semi-regular maintenance to keep it functional for future use, then spend a year carrying out work on the site to bring it up to scratch and into a guest ready state, to then intend on removing it again a year or two later whilst the park continues to lack non-coaster adult attractions is such a bizarre take. If the goal was temporary capacity to deal with Nemesis’s absence we’ll they already have the retro squad rides, even with Nemesis’s absence there are still more rides in the park with the retro squad rides (and without NST) as there were prior to the retro squad rides but with Nemesis.
The ride has been brought back as it likely was always intended that it would be, it’s a decent filler attraction without being anything mind blowing, which is fine, all works need rides like that and it serves it’s intended purpose. It’s arguable that if Alton had their time again that they’d have put the 2012 budget to better use, but they don’t, so it’s making the best of the situation.
As to why they haven’t sorted the restraints out, who knows? Perhaps a fix is en route, perhaps the decision was made that it isn’t enough of an issue to justify the expenditure, perhaps their isn’t a solution in keeping with their health and safety aims. I’ll tell you what it won’t be though, it won’t be because they’ve spent a year bringing back a 10 year old ride to mothball it again in a year or two’s time as that would be a massive waste of a budget.