It used to be that each team would have a schedule that was entirely based on where you finished. So, if you happened to win your division, you would have a tougher schedule because you would face more teams that won their divisions. And if you finished last you had a relatively easy schedule because you would play teams that finished last. There *was* a first and a last place schedule.
But, about 6 (?) years ago, they changed all that. Now the schedule works out thusly for everyone:
You play everyone in your division home and away (6 games)
You play another division in your conference - this rotates year over year (4 games)
You play another division in the other conference - this rotates year over year (4 games)
And then you play the two teams in the other 2 divisions who finished in the same place as you (last 2 games)
In Miami's case, they play the AFC South, the NFC South, as well as division winners Pittsburgh and San Diego.
Yes, its a tougher schedule than this year, but not because they won their division. Its really just by happenstance because they're playing some tough teams in the AFC and NFC South....