Square Enix is able to make a game that beats Final Fantasy VII in terms of quality:
Sources:
http://www.ign.com/articles/2012/06/26/square-enix-reveals-conditions-for-final-fantasy-vii-remake
http://www.destructoid.com/final-fantasy-vii-will-be-remade-when-ffvii-is-bested-230144.phtml
Jim Sterling wrote: Boss-lord Yoichi Wada has a new excuse today, claiming VII is yet to be improved upon, and can only be remade when a better Final Fantasy comes along.
"We'll make a Final Fantasy VII remake once we've made a Final Fantasy game that exceeds the quality of FFVII," he said, boldly defining VII as the best game in the series.
...Wada went on to state that no Final Fantasy released in the years following VII has been as good, and as such, any remake released now would effectively end the entire franchise.
Sources:
http://www.ign.com/articles/2012/06/26/square-enix-reveals-conditions-for-final-fantasy-vii-remake
http://www.destructoid.com/final-fantasy-vii-will-be-remade-when-ffvii-is-bested-230144.phtml