Not sure if I'd be too keen on getting Thad or Milsap-level player with a #4 pick. Think that speaks volumes about the quality of this year's draft.
Either you like Millsap a lot less than I do, or you have a much higher opinion of Jaylen Brown / Kris Dunn / Jamal Murray / Buddy Hield.
I would be much more interested in a Millsap-level player than a Thad-level player for that #4 pick. Millsap is statistically better and on a far superior team. Thad is decent, but has always been on that 'Jeff Green tier' and you can't trade a top lotto pick for that.
I think if you place Thad Young on the Jeff Green tier, you're either undervaluing Thad Young pretty significantly, or you like Jeff Green a lot more than I do.
Not to say Thad Young is an amazing player, but he's solid and consistently productive, which is more than I can say for Jeff Green. I'd take Thad on my young every day of the week over Jeff.
Anyway, I agree, you'd much rather have Millsap than Thad. I wouldn't trade a top 5 pick for Thad Young, either. But that's a spectrum. I think that range of outcomes is pretty good (solid scoring starter at worst, multiple time two-way All-Star at best) for the 4th pick.
I don't think there's a prospect in this draft who offers that type of range of potential outcomes outside of the top 2.