AD is solid no doubt and solid on both ends of the floor + already has a ring, just like Kyrie. But, yeah... each month AD healthy brings us closer to another injury and that's something that worried me as Lakers fan. Kyrie and AD are perfect fit I think, but they still got too many Centers and I think Kyrie shines when teams not focused on him solely. He hit the title winning shot with Cleveland, when most eyes were on LeBron and he balled with Dallas, when Luka still got the better defender. In Boston we saw his struggles when he was suppose to carry a team and Boston didn't have less talent than Dallas team...
Also, it's huge trade pretty late in to the season and Dallas still haven't even secured play-in spot, not to mention playoff spot - so they can't afford themselves to take much time to glue and Luka wasn't another player - he was Dallas. When he was on the floor, he owned the floor, so it will be hard I think for them to switch the disk (but who knows - maybe it will give others chance to shine).
Overall, I doubt they could have gotten a player of AD's caliber in return - can anyone think of a name? So it's more a question of AD's health (and that's a huge question) and if they made the right choice not to go for rebuild and get a ton of 1st rounders from Oklahoma for example...
Who they could have gotten? Zion and even worse questions about attitude and health? Beal? Embid and his health? Butler maybe the only one, but not sure it's better than AD...