Dallas has been incredible with this 5 man starting rotation. Think they are something like 16-2 with that starting 5. The lineup just works well together and really accentuates what makes Lukabso good.
In particular, PJ Washington is +156 in 29 games, replacing Grant who was -116 in 47 games. Per 36, Washington is +6.0, Grant -3.4. That is a big difference. Kleber has been playing more minutes than Gafford or Lively in the playoffs and the results with Kleber on the floor are much better, +7.5 for Kleber (best on the team), -7.5 for Lively, -8.0 for Gafford (worst and second worst on team).
If Kawhi can play at or near his healthy, mid season level, I still favor LAC. Without Kawhi, or with a less than 100% Kawhi, DAL certainly has a chance to steal this series. They "clicked" at the right time.
It is interesting (at least to me) that PJ Washington was -6.5 in 44 games for CHA while Grant was a little better, "only" -4.4 in 29 games (actually one of the better +/- of the CHA regulars, although Grant tailed of towards the end of the season). It is rare for a player to go to DAL and be better. More common for players to improve after leaving DAL.