I'm looking long term in the values at the QB. Rodgers will be a 10 yr stud IMO. You have him, barring injury, and you can lock that position down for the next decade and not have to worry about it. Manning is great, but he will start to decline at some point. So I do see this, in a dynasty league, as a pretty big drop.
Fitzgerald to White is much bigger IMO than you are making it out to be. Again, this is a lock down stud for many years. Fitz is just 26!! I know it seems liek he's been around forever, but he is just entering the prime years of his career. In fact, he is 2 years younger than White! This is the difference between having a year in year out top 5 WR for the next 5-8 yrs and having a top 10 WR for the next 3 years or so. This is a big drop off from Elite to very good.
Benson to AP. Your right, your getting a STUD RB who is young and damn good! At only 24 the sky may be the limit for what he can do. But he also has a lot of wear already as a young man and takes a lot of punichment with his style. How long will he hold up? Will his fumble issues get the best of him (doubt it, but never know). Benson is durable and while he got a heavy work load this year, was limited in the NFL till then. He's not AP, but he's in a run oriented offense and should be able to keep it up for 2-3 years.
Wild card: I'm going to toss out the relevence of the safety in this, a safety thast had 18 tackles last year is WW fodder. So this comes down to Donald Brown. In that offense, he could be the future feature runner and could turn into a very good #2 RB. He's only in his 2nd year so he still carries some good value. Tossing him in when you are already giving up 2 significant young long term solution to two spots to only get 1 in return is too much for me.
This deal in a redaft league makes more sense and is actually one I would do. But in a dynasty, there is no way I'm giving up Rodgers and Fitzgerald both, even if it lands me AP. This makes you dependant on AP instead of being well balancd as you are now.
If you sub in Crab for Fitz I would then likely roll the dice b/c you still have Fitz to anchor and you add White. You drop a bunch of youth in the deal losing Crab, but there is no gaurentee how great Crab will or will not be. I like that deal much better for you.