The Panthers have the best defense in the NFC South, but they lost their #1 passing option and that offense could look really mediocre. The Falcons still stink on defense with lackluster personnel despite their efforts to improve on defense through free agency and the draft, and the Bucs have a starting rookie QB behind a bad O-line. While the Saints don't exactly a studly defense (I think their defense is pretty bad) and lost some major players on offense, I feel people feel more safe picking the Saints than any of the other NFC South teams due to better recent success. You can't really call any team from the NFC South a contender unless something miraculous happens, and picking the winner of this division is such a crapshoot.
not saying any of the other teams are good, but last year Panthers ~= Saints ~= Falcons. Even with Benjamin out (tbh he wasn't all that good last year, but missing him will still hurt) I think the Panthers improved over last year, and I think the Falcons did as well. I can say with 99% confidence that the Saints did not improve, which makes me question the "safety" of picking them.
And, because I'm a Falcons homer and need to point it out, the Falcons were ranked 32nd last year on total defense and improved, the Saints were ranked 31st last year on total defense and got worse (in scoring, they were 26th/27th). One of those two teams just added the DC from the best defense in the last couple years as their head coach.
On the opposite end of the spectrum, I don't get the "doom and gloom" viewpoint of losing Graham by some people. The Saints don't need him to have a successful offense more than they need a top center like Unger to allow Drew to step up in the pocket. If you believe Payton when he says the Saints will run a more balanced offense this year, then the presence of Ingram and Khiry should take some pressure off Cooks and Brandon Coleman to produce (though they will be integral, especially Cooks). Consider also that last season was the first for Brees not to have a Sproles/Pierre Thomas or Sproles/PT-"type" pass catcher out of the backfield, which they have probably almost exclusively in Spiller this year as they try to get him in space unlike the uninventive Bills.
Defensively, it'll be a struggle. Losing Lewis already is tough. Browner isn't what comes to mind when I picture a CB1. Byrd and Vaccaro will be very solid on the back end though. Byrd also avoided the PUP which is great. Other than that, no high hopes on D.
I'm fully ready to admit my Saints could win the division and likely be anywhere from 7-9 to 9-7 in doing so. Health permitting, imo, they have the most talented team in the division.
You can't honestly say that losing one of the best offensive non-QBs in the NFL won't have a major negative impact on the offense. Graham was the most important cog in the Sean Payton-Drew Brees offense, and with him being injured/unproductive last season it definitely showed in Brees' statline (Brees had his worst season since 2010, waitforit, JG's rookie season). The offense will definitely have a new look this year, and some people might say that the change is good. From my perspective, as someone who is betting on whether or not the Saints will be better this year, change is scary. I honestly can't see the uptick in the running game making up for the decline in defense (didn't even mention the other JG, who had 30% and 25% of the Saints sack totals the last two years and is, deservedly, gone) and the decline in passing/red zone efficiency you lost when Jimmy Graham couldn't be paid. Still, stranger things have happened, and I'm a big believer in Brandon Cooks this year, and there's no reason to believe 2015 Brees will be any different than 2011 Brees.
