I believe the point that I and the others on the generally pro-Point Buy side are making is that, when you start devising all sorts of exceptions to the rule - Roll your character, but you can reroll, or switch rolls with someone else, or adjust stats in manner [X], etc. - why don't you just come up with a way for everyone to get the stats they want to begin with?
What intrinsic value do all those middlemen have, other than some sort of "I rolled my character, so it's more 'real' than your point buy character" cachet?
In fact, in the game I'm about to run, I've gone one step farther than Point Buy. In this campaign, players may set their characters' base stats (before racial mods) to any value they desire in the 3-18 range. Go wild.*
* - Then, figure out the PC's point buy value (scale modified to account for values < 8), and subtract a number from it. That's the PC's Hubris score (which may or may not ever have an in-game effect).