They shouldn't be farming ideas from social media, period. They should only do that if it's an idea that lines up with their plans.
Like Matt Murdock in NWH. Sure, fans demanded it but given the situation MCU Spidey was in, it made sense for Matt to show up plus Matt and Spidey have a long established history in the comics and both Cox and D'Onofrio have been pushing for their characters to meet Spider-Man.
Everything that NWH got right, MoM got wrong. There is no reason for Patrick Stewart's Xavier or Krasinki's Reed to show up besides meaningless fan service. Plus, it was a waste of Patrick Stewart, Benedict Cumberbatch and Elizabeth Olsen's talents to have their characters all in the same room and not have any meaningful interaction between their characters.