By all reports, Ainge wanted Winslow. You might not think he has superstar written on his face (personally I really wanted Stanley Johnson, but Winslow could be good as well), but apparently Ainge thought he was more valuable than all three players he ended up drafting when he couldn't make a deal.
In the past, Ainge has reportedly been similarly interested in Tyreke Evans, Harrison Barnes, and Joel Embiid, among others. This year there was some talk he was also trying very hard to trade up for Jahlil Okafor, with no luck. Make of that what you will.