If it can be done, eventually it will be done. It's inevitable that people will eventually propose all manner of changes to bitcoin, some good, some stupid. Real bitcoin (or original bitcoin) could still continue to run as its own fork, in the background, waiting for the market to decide on a winner. Just as it is inevitable that developers will propose a small infinity of bitcoin-derived altcoins, trying to capture the windfall of a self-published bootstrapped currency. But very few altcoins will become successful networks in the long term, a smaller and smaller percentage of new coins as time goes on.
Either Hearn and Andresen are correct, in which case their success will speak for itself -- even if they totally screw over the large bitcoin bag-holders in the process. Or, XT will become an insecure, centralized network and will die off on its own. No need for politics, in this case mathematically dictated incentive structures will decide who wins.