While 31 is a bit of a stretch, it's not too terribly far off based on what we know now, which is very little. This team has WAY too many question marks automatically expect good things.
The o-line was the biggest issue last year. We gained Albert, but lost Pouncey for at least half the season (I'm betting longer). After that, we are relying on rookies and guys who should only be backups. Question marks.
I have faith in Tannehill, but if he fails to improve over last year, we'll be in the market for a new QB, once again. Either way, you can't count on him as a sure bet. Question mark.
Our RBs are a huge question mark. Everybody is touting Miller as if he did anything last year. He didn't. He certainly didn't show me anything that makes me believe we can count on him. As for Moreno, sweet, another injured player brought in, and one with a single good season to his name. Question marks. (No need to mention Thomas. He sucks. It is known.)
Our WRs are easily the best part of our offense in that they are a known quantity for the most part. That known quantity is an average to slightly above average unit. The only real question marks are whether Wallace can live up to his hype and whether they can become more durable. I loved the Landry pick, but I also love that we aren't relying on him as a rookie. He makes me less concerned about durability issues.
TEs are huge question marks outside of Clay, who isn't strictly a TE, and Egnew, who sucks.
I like the potential of Lazor, but reading stuff on here, you'd think they guy has a proven track record of some kind. Question mark.
As for the defense, our DL is good again, though losing Soliai will hurt. Losing Jordan won't hurt, which isn't something you want to hear about the third overall pick that you traded up to get, but that's another topic. Our LBs are mediocre at best, but only because of Misi. The secondary is the biggest question mark on the defense and second only to the offensive line. There is one proven commodity in the entire unit: Grimes. The rest is betting on injury prone players, (essentially) rookies coming off of injuries, and a safety who took a step in the wrong direction last year. This in a year when we get to face Brady twice (obviously), Manning, Rodgers, Rivers, Cutler, and Flacco.
Fields is awesome.
Again, I think 31st is silly (offseason power rankings are ridiculous in general), but not that ridiculous based on what we know, which is very little. Of course, I see very little difference between being the 31st best team and the 20th best team. Neither is likely making the playoffs, so who cares.