I don't know why people expected Uematsu to be involved in the first place. Nobuo has only been involved in two SE products since the merger and his relationship with the company has been pretty strained ever since, due to location changes, the fact that he now produces freelance for many other titles and seem to be prioritizing those, and some issues with copyrights on his earlier works.
Umatsu's forte has always been composing in either case, for more than production on a general basis. He's great at creating original melodies, but personally, I think a lot of other artists have done a better job of arranging those themes than Uematsu himself.
FF7 already has a soundtrack. It's already been composed. They don't need Uematsu to re-arrange or supervise the production of higher-quality variants, as this job can be done by pretty much anyone as long as they have his original score to work off of, and granted the fact that there are many producers who're more skilled than him in that regards, it makes more sense for SE to take that path instead.
To clarify before someone feels the need to jump down my throat though - No I am not saying Nobuo isn't a brilliant composer. To my mind, he's the best contemporary composer of music period - because the melodies he makes are pure genius. However, he is not the best producer or the best arranger out there - there's a big difference between these aspects of creation music.
Personally, if they're going to have someone else interpret and renew his work, I'd like someone really high-end like Kannou Yoko (probably the best producer in Japan in my opinion), but that's really really unlikely to happen.