Their main problem is they're missing a lot of 3s. And they shoot a lot of them, so they can die by them.
In OKC, they were missing almost every 3 in the first half, then came back strongly at the finish to shoot over 30% 3s. I think that's how I remember the box score. They shot around 30-35 3s, which is about normal in the NBA today. You shoot over 40, you are probably shooting too many 3s.
I wish Stevens would designate guys as 3P shooters. I think it's unwise to have some guys shooting 3s who can't hit at least 34% of them--the level where the 3P is preferred over the 2P. That just drives the 3P shooting % down, and loses games if you shoot enough of them.