IMO Cleveland kinda had to do this deal because they can't afford another under 30 win season. Especially since the price they paid for Deng is more than fair.
When you think about it, this is their 4th year of tanking/being bad, how long does it takes for Irving to become another all-star wanting out? They will extend him next summer but they have to put some pieces around him and show him he can win there if they don't wanna decision #2.
They have a collection of young players that are without real veteran leadership, adding another young player/project won't bring them any closer to playoffs.
We all agree that a thought about TOP5 pick in this year draft sounds great but it's only potential. Can someone guarantee that Wiggins will be borderline all-star, two way player like Deng is today? No, especially considering their draft history.
Also, Deng is only 28 so even if they give him Iguodala's money (4y/48M) they can expect high quality play from him.
If things don't work out this year, they can let him walk and still have extra picks and cap flexibility.