NFL.com says "Last season (2015) marked a downturn for him (Brees)..."
In 2015 Brees was in the top 10 of every QB stat except for interceptions, which he was #12 (min 300 attempts). The Saints led the league in offense yards, and ranked #8 in points. You can't ask for more from the guy.
He can't play defense too. The Saints defense ranked #2 in defensive yards and points given up. An offense can't overcome that very often. With a terrible defense, they still managed to win 7 games. Hell, just a few years ago the Saints set the all-time record for the most yards allowed in a season.
I don't expect much different from the Saints in 2016. We are one game in, and it looks like more of the same. They scored 34 points, but gave up 35. Brees threw for 400+ yards and 4 TDs with no interceptions. He even threw a franchise long 98 yard TD to WR Brandin Cooks.
At 37 years old, we can't expect more than a couple of more good years out of Drew. Even the all-time greats (which he is one) hit a huge wall in their late 30s. By 37, most have already hit that wall, but even ironmen like Favre and Peyton eventually can't do it anymore, and 39-40 seams to be the absolute max.
Brees will be in Canton one day and the Saints will kick themselves for wasting his last few productive years. At least that's the way it's heading, but I would love to be surprised. We'll see.