It's a good deal for us (both teams frankly). How many of us were moaning and groaning about needing to sign IT to a max contract at the end of the year? Lot's of us were, and for good reason. no telling how much longer he could sustain that level and the injury now makes it a slam dunk for us.
And yeah, projecting what kind of player that Kyrie will be is part of the job. If you can't handle it, perhaps you should stay in the shallow end.
And that's a far cry from trying to predict and as yet known draft pick at an as yet know position drawing from an as yet know talent pool. Sure, some of those high school guys may be good. But if history is any indication, some of them will disappoint and the odds of anyone of them becoming a franchise player (or even as good as Kyrie) are not nearly as high as you think even in the top 3.
So sure, I'll take my chances on a bird in the hand who's a gold medalist, champion, perennial all star at the age of 25 over the possibility of maybe getting some guy that will be good in three years. Hell, we still have the lakers/king pick and we already have too many young guys anyway.