with regards to the lack of approval, could it be that Twitter want to avoid app redundancy to save resources? 100,000 of these requests can't be cheap for them, so when there are already multiple apps do what this one does does it not make sense for them to say they're no longer supporting most to save money?

I could be way off the mark, but that's how it appears to me. Multiple apps with the same purpose that require lots of resources... makes sense to stick with one or two high users and limit the rest.