The problem with this is that it might be fair for the premiership team, but for the rest of the top 4 it is going to cause howls. Its one thing if they're a Sydney/Hawthorn/Geelong that have been up for years. But if (say) Richmond made a preliminary final this year, or the two years North made it, or if last year Bulldogs had lost to Sydney, none of those teams were strong enough that they should be stripped of picks.
Obviously if someone wins, then they don't need one, but one pick isn't making that much difference. And smooths out the bottoming out process potentially.
Because its damn hard to win a premiership, and the reality is you can do a lot of things right and still spend years in the wilderness. Especially if you've got structural disadvantages like Brisbane do. To reduce the time spent rebuilding, which keeps fan engagement/hopes up as well, improves the quality for every AFL fan whose team doesn't happen to be a superpower at that point in time. We (fans) all live on hope, a system that removes it is not as good.
That sometimes teams were partly to blame for their current predicament shouldn't cause us to say, well stuff their fans for a decade, your crazy Vossy got you there and its your own fault. I'm personally fine with giving them a little hope back.