THIS year.
I understand the argument for 2018: We don't know how good the class is, and 1st in 2018 gaurentees a shot at the best player in the draft. We know how great 2017 is for the most part and any of 5-6 players projected in the top ten may turn out to be the best player of the draft. Assuming the nets pick doesn't get worse (looks like a safe assumption) the Celtics are already in the money for the best player of the draft this year. Making next year's pick a certain #1 is the smart thing to do.
THAT SAID---
Fultz is out of this world. He is clear cut better than everyone and I think there's more of a drop off between him and Baal than there is between Ball and the next 4-5 players. Fultz is a transcendent player and even though he doesn't fit our team, he's just THAT GOOD that I take guaranteed Fultz and run laughing all the way to the bank.