Rondo is a better jump shooter now. The reason he shot 40% is because he couldn't finish at the rim this year as well as he has in the past, took less shots at the rim than he did in the past, and took more 3s (while shooting a career high in attempts but still a bad 28%)
That's scary on two levels, shooting a lot of 3s is a problem when you're bad at it. And we have to hope that his ability to get the to the rim returns as he hits the full recovery time for his ACL injury.