Why must playoff seeding....

... be fixed by standings? Why not allow the #1 seed choose which opponent it prefers to play?

Right around April each year, we start saying things like "Yeah, it seems like it almost would be to the [team] to lose some of their remaining games so as to be matched up with [some other team], because as of now, it looks like they'll be playing [some third team] and they are [streaky; a difficult team to match up to, considering team #1's weaknesses/idiosyncrasies, etc.]."

However, if we allowed the top seeds to choose which team they will play in the first round (and perhaps even the 2nd), then there would be no opportunity for such strategic-losing.

I've come across some similar 'replace accident/luck aspects of sports with rational decision' arguments in recent months. For instance, Tim Harford has written a few articles for Slate (here) making the case for replacing the coin flip in football with an auction (i.e. "Whichever team is willing to start with the ball as deep into their own side of the field gets the ball first.").

So I'm curious as to what the downside would be to allowing such elective playoff seeding. Here are a few stabs at it:

1) Imagine somehow a lower seed (but not the #8) concludes that it would rather play, say, the #1 than the #2, #3 or #4. Then here's an example of how strategic losing would still be a problem, even for the elective system.

Response:

1a) If it's possible to conclude something like '#1 is a better matchup for our team than ____', then it's just as possible for the #1 seed to conclude that 'Even though [team that sunk to #8 late in the season] struggled the last few games of the year, we don't match up well with them, so let's pick a higher seed.'

1b) Such strategic losing is just as possible in the current system as it would be in the elective system.