For instance the ending, it's really loose, how could they improve it?
One of the ideas was that Geralt and Yennefer make Kaer Morhen their new home.
They won't be involved in political matters anymore
They can do what they want there
Maybe offer training, sword and magic
I think this would help much more than "the ending sucked, change it."
I can imagine they put a sign outside Kaer Morhen
"Swords and Magic School (aged 10 and below)"
PS:No snotty kids