I don't care if Kemba is slightly worse than Kyrie. Is IT better than Kyrie? No, but we have better record with him because he plays within the system. The only reason the Cavs almost swept them in ECF is because he was banged up at that point.
With the Celtics now, Kemba doesn't have to shoulder the whole offense. Basing his character and reputation, I think he's more willing to defer to the young guys, much like Shaq was to Wade. If winning is Kemba's priority, he'd do everything Brad will ask him to do.
Not to mention, we won't hear any drama from this guy. He's a known leader in that Hornets team despite their lack of success.
As for bigs, we have cheap ones available for MLE or min. Guys like Bogut, R-Lo, Dedmon, etc. are on the market.