Alshon Jeffery was the #1 receiver for the Bears in 2016, not Meredith. Also, we'll be three years removed from Meredith's one productive season, and what we saw from him last year was anything but promising.
P-Rob will certainly make us better, but PJ was surprisingly effective last season, so it's unlikely to be a big improvement.
While it's a young team, it's hard to deny that this team will only go as far as Drew takes them. Without Drew, they'd probably be looking at a losing season. And I think the case for pessimism is that Drew's performance fell off a cliff last season once the OL started falling apart. If the Saints don't have the combination of an elite OL & Drew Brees, they're going nowhere. And with Unger's surprise retirement, in addition to having only one draft pick in the first two days, it's not unreasonable to recognize that the window could be closing before our eyes.