A lot will depend, I think, on how good Lawson is in the Red Bull. I think he is going to be a definite upgrade on Perez, but yet to be seen how many points he is able to take off the competition (McLaren, Ferrari, Mercedes). I think the same goes for Kimi.
I believe next year McLaren will clearly have the best driver pair at the start of the season (while all 3 competitors have a new driver acclimatizing to their surroundings), so there is an early season consolidation that needs to happen.
The best pairing will depend on how Lewis fits at Ferrari, and with more of a reach how Lawson is at RBR.
If Lewis returns immediately to his best form then well,,