Carter-Williams provides exactly what the Bulls need in being a competent backup for not only Rondo, but also the aging Wade, who will need to be rested often throughout the season. The only issue I have with this is that Carter-Williams' skillset could be somewhat redundant with that of Rondo's: both are lengthy defenders (though the edge goes to MCW there) with exceptional passing ability (much more so Rondo than MCW, however), who lack a reliable jump-shot. With now Rondo, MCW, Lopez, and Gibson all being unable to create their own shot on a consistent basis, the onus now falls on the star, Jimmy Butler, to be the go-to guy for this offense. It is critical that the aging Wade and the up-and-coming Mirotic and McDermott provide help for Butler in this department, but none of the three are an especially safe bet to do so on a large scale.
In terms of what Chicago gave up in this trade, they did all right. Behind Butler and Wade, the team wasn't particularly overloaded, but youngsters like McDermott and SG Denzel Valentine can easily provide necessary spacing as well as relief for their starters. Thus the loss of sharpshooter SF Tony Snell won't be felt too hardly in the Windy City. Thus GM Gar Forman is to be commended for his excellent work of acquiring a high-upside point man like Carter-Williams at little cost, who will help this team continue its effort of making deep playoff runs, even with a fresh roster.