So overall trade would be:
Saints get
Malcolm Butler
Pats 3rd round pick
Pats get:
Brandin Cooks
Saints 4th round pick.
So this sums up Chop's expectation perfectly.
Agreeing with your assessment that a corner is worth more than a wide receiver, why would the Pats make that deal?
Additionally, Butler is a proven stud of a corner. Made likely the best and most clutch Super Bowl play ever, has had All Pro years for two years since. Covers much bigger than his 5' 10" size, leaps like a jack-in-the-box, rarely misses his coverage, hits hard, and is a sure tackler. How many corners make tackles behind the line of scrimmage. Butler does. He is athletic, smart, and tough. And a good citizen. And a Patriot who knows what it takes to win. And the Patriots need him to anchor their defense in the passing league of 2017.
Cooks? Not bad. Pretty good receiver. May turn into one of the great ones. May not. Has a reputation for sulking when not the primary receiver.
First, the Patriots don't need him, regardless of how good he is. They had the second best offense in the NFL without him. Secondly, they sure don't need a me first attitude guy polluting the team. Why do they need to even risk that? They don't.
So from a Patriot perspective, the deal as outlined above stinks. Saints get the better, proven player at a coveted position. Pats get a risk player at a position they already have well covered.
So minimally, IF the deal for Butler gets done with the Saints the deal should look like this:
Saints get
Malcolm Butler
Pats 3rd round pick
Pats first round pick in slot #32
Patriots get
Brandon Cooks
Saints 4th round pick
Saints first round pick in slot #11
That looks more fair to me if this deal must go through. But honestly, we already have Cooks. We'd would MUCH PREFER to also keep Butler, either by matching a Saints offer, or by keeping him for the 4 mill and address resigning him at this season's conclusion.
PS I also have a theory as to why the Pats traded for Cooks, a guy we really don't need. But that's for another thread, another time.