To build on Greg's comments, I think it's also important to remember that the TO has the final say, so ambiguity doesn't give the TO more flexibility. That person already has all the power they need to make a decision. If the TO disagrees with an FFG ruling, he/she can disregard a ruling altogether (as Erick's comment above points out) or interpret the ruling differently based on the "consensus in the room."
The problem with ambiguity is that, at this point, the TO is going to have some personal opinions on the definition of sportsmanship/rules and may even have an opinion on what happened at worlds in 2011 and 2012. Most TOs are going to do what they feel is fair and/or standard, but because FFG still hasn't explained why players at worlds were disqualified, different TOs will interpret the ruling differently. Should we ban players who run the same deck if that deck has a combo that feeds off similar decks? If so, do we only ban those who are seated at the same table? Or only those at the finals table? Do we only ban them if they are at the finals table and king-make each other? In-game king-making hasn't been against the rules in the past…has that changed? In short, at what point in the tournament should we ban them, and for what? Letting them "run amock" throughout the whole event, creating NPE moments, and then banning them at the very least moment seems like a lose-lose for everyone.
Reasonable people will disagree with what FFG's ruling means, and how it should be interepreted. This is where the real problem lies. Ambiguity significantly increases the risk that tournaments will be judged completely differently by TOs who are attempting to decipher the new meaning of "standard practice." I am fairly certain that differences in rules interpretations were a contributor to what happened at worlds this year. Specifically, it was elluded to (if not outright stated) at GenCon 2012 that in-game king-making wouldn't be considered collusion, so long as it wasn't premeditated. Fast-forward a few months, and this seemed to be a factor in the decision to DQ. As the 2012 world championship points out, one person's views may not align well with another's.
Without further clarification, the best case scenario is that any melee tournament will have "local interpretations" of the rules. GenCon's rules will continue to be enforced differently than World's, which may be different from Stahlecks, etc. If the point of a tournament is to identify "the best player," then the best player will be someone who shares the same personal opinions on sportsmanship as the TO. (Note: This cuts both ways. Someone who refuses to king-make may miss out on opportunities for advancement at a tournament where king-making is allowed.) At worst, the TO of a regional event will disqualify someone who unintentionally violated the the TO's version of the rules…or may have to avoid playing altogether because they brought the same deck as their metamates.