#imagine Rook finding out about Felassan's final words to Solas and using that

[social-cocoon]

This is just a quick thought but I think I would have enjoyed the redemption ending more if it had been a dialogue check like gaining Mythal's help or the Landsmeet in DAO. Like you have to pick things that specifically resonate with Solas, and you can get bonus points from the Inquisitor (determined by whether they chose to save or stop him and whether he was romanced or not) and from Morrigan/Mythal assuming all his memories were witnessed and Mythal's essence recieved, so this way it's less Mythal being the only one who could really get him to stop and more that the people who actually fought for the current Thedas are the ones to change his mind.