Meh. It's a hit-or-miss league. Any of those bench guys can go cold and several at a time is very possible.
I love the BWA, but let's not kid ourselves. They need another scorer like Jamal Crawford for certain situations.
A scorer would be a nice but IMO it is not a necessary addition.
These needs can be resolved with good rotation management and we have the best man alive for that task in CBS.
There's a sort of "equal and opposite" conversation going on about how the Celtics are going to keep all of their scorers happy, since Rozier/Brown/Tatum got so many shots in the playoffs and will now have to cut back on their touches. There's a mainstream concern that those guys will get all disgruntled by their unsatisfied appetite for shots.
I agree with you that managing the rotation is all that's needed to keep scorers on the floor. Hayward, for example, would make a good pairing with Rozier, since he can run a pick and roll as the secondary ballhandler with Terry off the ball.