I will say this up front. Shows, are important; and that they should not be keeping that venue (and TLT) vacant. But think about this:
Universal Orlando is currently beginning work on a multi-billion dollar expansion project, and that things can and would need to happen to lower costs around resort.
Cutting an attraction that had virtually no love like Sinbad, will not make a huge dent to the park. And considering the odds, it should've been sooner than later, when you consider the operational costs alongside the GSAT's for Sindbad.
Would you rather want a horrible show with low viewership, or a horrible show with high viewership to stay at the parks? While we rag on Fear Factor all we want, it benefits the USF park; and has a huge venue nestled in-between Potter, Men in Black, and Simpsons.
It absorbs people a lot better than Sindbad ever did.