To answer my own question, I see Donovan has just 1 goal and 1 assist in 16 games with University of Wisconsin. Suffice to say, Thompson looks like the superior prospect now. What did the Devils scouts see that we missed?
Just purely a guess here, but here's what I'm thinking...
As propsect-oriented hockey fans, we tend to focus a lot of our attention on the young players that are going to be draft eligible
for the first time. With 32 points in 60 USHL games in 2017-2018, Thompson was not even worthy of a 7th round pick. He was actually undrafted
twice. That said, I imagine that if he lit up the scoresheet for Providence in his freshman year, we would have known who he was. Maybe he still wouldn't have been a first round pick, because of his age, but probably at least a second round pick. But a guy that gets passed over twice and then puts up okay numbers in his freshman year is not going to make casual fans sit up and take notice.
NHL scouts, on the other hand, have a very different perspective. They watch these NCAA games closely, and will notice an undrafted kid that is playing very well, even if he isn't putting up a ton of points. The Devils had to assume that they weren't the only ones to notice this kid, so they couldn't risk waiting until the 6th or 7th round. So they used a 4th rounder on a kid that had some warts (double overager, limited offensive production to that point), but also upside. Which is like every other mid-late round pick when you think about it. They sure didn't
know he was going to pop, but they knew he
could, and in this case it worked out. The funny thing is, if he had fizzled in his Sophmore year, we'd all be killing the Ray and the scouts for that wasted pick.