In a lot of ways it doesn't really matter what the answer to this question is. Even if you think complacency could set in due to running it back the C's really don't have much of a choice. The 2nd apron restrictions make it very difficult to shake up the core in any real way. About all the C's can do is a 1 for 1 trade where you take back somebody making less than the guy you send out, and the amount of deals like that where you trade a rotation player and also get better is very tough.
Running it back makes sense because they won, but also because they sort of don't have much choice.
This is true for filling in the pieces around the top guys, but you can always shake it up with trades. Last off season, they traded Smart, Brogdon, and Williams, all starters or near starter level players. Sure, letting Svi Mykhailiuk go to make room for a rookie (Scheierman), is not "shaking it up". But there is nothing stopping the team from trading say White or Holiday or even Brown (contract extension trade restrictions notwithstanding).
This team/roster, as currently constituted, is heavily invested in Guards and Wings, and less so in Bigs. Trades aren't easy, but for example, it would not be unthinkable to trade say White or Holiday for a starting PF. You don't do that trade unless the PF coming back is a solid starter. Or maybe you trade Holiday and get back 2 players, a PF and a wing, for the same money. That could make you deeper, maybe more balanced, but less top end talent.
I am not suggesting any of these trades are the way to go at this point in time, but they could do it if they wanted. They have made a conscience decision not to "shake it up" right now, not surprising since they just won a title. The landscape could be different in a year though.