Exploring How the Saints Could Trade Up for Cam Ward

The sample size is also really small for trade ups. How many QBs were drafted over the past 20 years that involved significant trades?
You could do some research yourself... first search hit I got was an ESPN article from 2021, listing them all to that point in time (according to them).

Between 2000 and 2021, 1st round, top 1-10 picks:

Josh Rosen 10th overall - bust
Mitchell Trubisky 2nd overall - bust
Robert Griffin III 2nd overall (who wasn't a bust really, he got hurt, but still...)
Sam Darnold 3rd overall - bust for the Jets/Panthers/9ers (we'll see with the Seahawks)
Jared Goff 1st overall - Rams/Lions teams so good, they won a lot of games even with him at QB
Trey Lance 3rd overall - bust for the 9ers, on his 3rd team.
Carson Wentz 2nd overall - bust
Blaine Gabbert 10th overall - bust
Mark Sanchez 5th overall - el busto supremo
Michael Vick 1st overall - was doing well, until...

1st round:

Tim Tebow
Kyle Boller
DeShaun Watson
Paxton Lynch
Johnny Manziel
Teddy Bridgewater
Paxton Lynch
Josh Freeman
Brady Quinn
Jay Cutler
Jason Campbell
J.P. Lossman

Before 2000, not pretty either... you got Ryan Leaf, Jeff George, Steve Fuller... Steve Bartkowski...

The only 4 successful QBs that have been part of a draft day trade for a pick in the draft are Josh Allen ( 7th overall, no SB yet), Jordan Love (26th overall, 1 season, got to see more), Lamar Jackson ( 32nd overall, regular season MVP, irrelevant in the playoffs), and Mahomes.