That Kane/Bogosian trade was terrible. As was the Okposo signing. Yes, there's been mistakes.
The Kane/Bogosian trade is certainly up for debate; however, Myers name is frequently thrown around in the trade rumors section by everyone including Jets fans. He's pretty good-- but he's not THAT good. And he's also not as valuable as some would like to push. And Stafford is solid, sure. We don't know what Lemieux will contribute at this level yet, and Armia seems like a ridiculous set of tools but without a toolbox kind of player. There's also Roslovic, but again, unproven. Kane is an immature ********, but he's an absolute physical force on the ice, and Bogosian for sure has his ups and downs. You could tell me he can't stay healthy and you'd be right, but it's offset by Myers and his injuries. There are just a lot of different pieces within this trade that are either too soon to judge, or too "meh" to really point at and say OMG TERRIBLE.
But in reply to the bolded... are you ****ing kidding me? Not only is it anything but a terrible mistake, the Okposo signing was, in a way, a message to the other UFAs around the league that Buffalo could do some damage in the Eastern conference pretty soon, and he chose to go to a small market team with a pretty low-brow reputation rather than stay in the big apple, or even go to another more "desirable" destination because he's buying what the Sabres are selling. And without being seriously overpaid. Now, we will obviously have to see how he performs this year, but calling it a mistake before he's even played a regular season game in the blue and gold is just silly.
But to answer the OP's question, I'll say they either just miss, or they just make it in. I think they're right there, but will need some help from within the conference to have a chance. i.e.. teams like Boston or Detroit to decline more rapidly than most of us are expecting.