If the Raptors are REALLY going to go for winning a title, they would trade out Barnes and keep OG. I get why they might not want to do that long-term, but in the short term, OG is more ready to compete at a championship level than Barnes is and I'm not sure how Barnes and his 29% 3-pt shooting would work off of Dame.
Poetl/Siakam/OG/Trent/Dame is a LEGIT lineup and I think is more able to compete for a championship than if the Raptors were to swap OG for Barnes. Also, they might not have to give up as much in Draft capital (which they don't have a lot of) because of Barnes less expensive contract and greater youth.
It fits the Blazers time-line better as well as a Scoot/Sharpe/Barnes future is full of losses for now but pretty bright for the future.
That said, I don't think the Raptors give up Barnes, but if they want a title, I believe that would be the better move for them.