Would it be possible to implement this directly from the Bitcoin blockchain, creating a split? Where the current holders of bitcoins now are also the holders of Bitcoin 2.0? And then people will be vested in both with a market between the two, eventually finding out which one "wins."
This is how I would go about it when making an altcoin, too. But for most altcoiners the appeal is that they can be early adopters with their new coin. You don't have that with the bitcoin 2.0 approach.
Still, I'm not so sure how good it would be to fragment the Bitcoin economy.
Just fragment it once, on say Feb 1, 2014, to test it out and see how everything is working, with the complete understanding of everyone that, if the 'treecoin' implementation works, you will 'fragment' again on March 1st, 2014, with the intent of hard-forking THAT into new Bitcoin.
Therefore, passive users can coordinate to use Bitcoin Chain, knowing that their BTC will convert to Bitcoin Tree on March 1st if all is well, and not worry about any messy stuff in between. Those using Treecoin between Feb and March will get them for free but know that they will eventually lose them, making for a perfect test environment and no financial instability. Best of both worlds.
This is a very good suggestion, how a hardfork should be implemented.