By all accounts, Both the Vikings and the Bills each won the trade. Bills needed a bonafide #1 and had the cap space to make it happen, Diggs was unhappy in Minny, and the Vikings used the pick they got to draft Justin Jefferson who is playing far better than they could have hoped at a fraction of the cost.
Could they have drafted Jefferson? Sure, but the draft is a gamble and there was no guarantee that he would have been there when they picked so they made the move to get a known commodity in Diggs.
All in all, Beane has been great for them, far better than Hurney has been for us. He has put together a roster with depth and players that contribute (positively) to the team throughout. Something Hurney really sucks at doing now.
What are you going to do though?
BTW, you forgot to mention Tre'Davious White, one of the best Corners in the game right now (Drafted by Beane).