Kemba has been so disappointing since leaving Boston. I don't think he'll help Luka or Dallas at all.
I am not even sure Kemba is an NBA level player anymore. He can still shoot and score some but is not a prolific enough scorer anymore to outpace how much he hurts you on defense. He is a net negative. His NBA career looks over to me. He is only surviving on name recognition and reputation. Without that, he'd already be out the door.
I'd love to be wrong though. Kemba did a great job for us early on in his Boston career and he is a great guy. But I am pretty pessimistic.