Yes, in fact they did. From what I read on ff7shrine.com, so many Aerith fans wrote to Square about how angry they were for killing her off the way she was, as well as supporting their claim that she was "originally" meant to stay alive until the end, using evidence such as the infamous "ghost" that appeared in the church where you actually get acquainted with her. But mostly, it was just millions of fans that got pissed at the mere fact that a main character was killed halfway through the game and never had a true resolution/happy ending.
Surely enough, Square listened to their feedback, which might have been the possible reason as to why Final Fantasy 8 did not kill off the main love interest and thus became a less complex, more predictable storyline.