The intellectual giants in the national sports media just can't understand why the Chiefs would trade up to draft Mahomes. We've won 43 games in 4 years, including going 12-4 and having a first round bye last year. To them that means we should do nothing to prepare for the future and instead only make moves that help us in the immediate future. So today we'll placate them. Instead of giving up 2 1st round picks and a 3rd rounder for Mahomes, we are going to use those picks to acquire Drew Brees.
The first question, of course, is would the Saints do it. If they were willing to rebuild, I'd say yes. Even with Brees they don't seem particularly close to competing for Super Bowls, and he only has a couple quality years left. Those picks could help minimize the amount of time they spend rebuilding for the post-Brees era. For comparison, the Chiefs gave up less than a 1st round pick when we traded for Montana. The biggest issue is the cap numbers. Trading Brees would actually increase his cap hit for the Saints this year. But if they wanted to commit to a rebuild, not having cap this year wouldn't have been an issue.
On the Chiefs' end, cutting Smith would free up enough cap space to not only cover Brees, but also eliminate the need to cut Maclin. If we decided to not care about our long term future this trade is easy.
Now that we have Brees instead of Smith, how does that effect our team's performance? Here we need to make a couple assumptions. First, we're going to assume that Brees will play at a similar level to last year. Secondly, we're going to assume that the Chiefs and Saints have similar offensive talent outside the QB position. You can quibble with that assumption, but I would argue that it's close enough for an offseason fanpost.
In 2016 the Chiefs ranked 17th in expected points added on offense with 34, while the Saints ranked 4th with 182. Without turning this post into a statistics class, expected points are essentially the amount of points attributed to the offense once you factor out starting field position. With the Chiefs now having Brees, we will be the ones ranking 4th in expected points added with 182, and increase of 148. To get to actual points scored, we add that 148 to the 389 we already scored to get 537.
So now the most important question. How will that actually improve our win/loss record and chances of winning the Super Bowl? The best way is to look at the Pythagorean Record. This is an estimate of what a team's record should be based on point differential, and has been proven to be more accurate in predicting future results than the actual record.
Last year the Chiefs were at 10.1 wins, which was good for 4th in the NFL (behind New England (12.8), Dallas(11.0), and Atlanta (10.9)). If it wasn't for the Patriots having an unusually good year the Chiefs would have been right in the mix among the top teams in the NFL. With Drew Brees leading the offense, that number jumps to a nice round 12.0, putting us at a solid #2 and less than a single win behind New England.
Looking at historical QB's of Brees' caliber shows he should have another good year or two in him. This trade would have had made us one of the top 2-3 teams in the league, if not the best, for likely 2 years. However, without those picks we would have a hard time finding a QBOTF once Brees retired, and we know firsthand what that struggle is like. As it stands now, if Mahomes reaches his potential, we will have the most important position in sports filled for the next 15 years. Personally I believe in Mahomes enough to rather have him than Brees.