It all comes down to your personal preference and what sort of world you want to play in.
The most common refrain from people who advocate soft tanking is, "There's no difference between winning 60 games, and winning 65 games."
To me, there's definitely a difference. I would much rather win 65 than 60. I would much rather win 70 than 65. I would much rather win 75 than 70, and I would much rather win 80 (or specifically, 81) than 75. To me, the fun of the game is trying to be as competitive as possible, all the time. If you are in a competitive world (that doesn't allow tanking/traderape/etc), then the playoffs are sort of a crapshoot anyway. Sitting on top draft picks year after year to build a super-team is like using a cheat code... it's just not really that interesting to me. But again, that's just me, and anybody can play the game the way they want to. I just don't want to be in that world.
Additionally, there's talk about MWR screwing over people who have bad luck. But what soft tankers don't realize is that "good luck" can also happen. My World Series in Happy Jack came following a 79-win season. I improved my team a little bit, but figured I would be in the 85-win range and hopefully sneak into the playoffs in a weak division. I wound up winning 103 games and the World Series. So you never know when that little extra that you think bumps you from 70 to 75 wins actually winds up bumping you into the playoffs. Or that little extra that you think goes from 80 to 85 actually makes you go from 80 to 95.
And yes, I do think that any owner who can't rebuild on that progressive scale is not a competitive owner. Even in good worlds, you can build a 65-win team out of scrap heap FAs.