Before I get into grading this trade. I just have one thing to say: HOLY SHITTT!!!!! WHAT IS GOING ON??? This is easily the most shocking trade in NBA history and I have spent the better part of the last hour walking around my house screaming WHAT!!! Grading a trade of this magnitude seems arbitrary but I will do my best.
Mavs grade: B- Early reports indicate that Luka did not request a trade, which I find extremely hard to believe. There is no logical explanation that I can think of that would justify the Mavs moving off of Luka without him requesting a trade. With that being said, a potential lineup of Kyrie-Klay-Marshall-AD-Lively with a bench of Hardy-Grimes-Christie-Washington-Gafford is terrifying, but it's tough to envision what this team's true ceiling is as neither AD nor Kyrie profiles as an offensive #1 at this point in their careers.
Lakers grade: B+ To be clear, there is no historical comparison for this trade, but the closest thing I can think of right now is the KD to Phoenix trade, as this Lakers team profiles very similarly with 2 players who need the ball in their hands to be successful and a supporting cast ill-equipped for their needs. A lineup of Luka-Reeves-DFS-Lebron-Rui with a bench of Vincent-Knect-Reddish-Vando-Hayes can put up points in a hurry, but without any elite perimeter defenders and no great shot blocking, I'm not sure how this team gets stops.
Now, if you will excuse me, I'm going to stare at my ceiling for the next hour while I process this.