But what's unreasonable about a seeding formula that prevents Nadal from playing another Top 4 seed (which with clay weighting would probably be Djoker, Fed, Nadal, Ferrer) before the semis? I'm not interested in whether there's a Rafole final; I just want to see seedings reflecting reality. And the reality is that Nadal is odds-on to make the semis.
A formula is in principle better than just a decision by committee, as long as it is a reasonable formula and it is published well in advance.
The difficulty comes when a tournament decides to use a new formula when it has not done so in previous years, and when it decides just a few weeks before the tournament is due to start. This is especially a big problem when the tournament admits that the only reason for doing this is because of the current ranking of a specific player. Any formula produced is likely to be viewed with suspicion, e.g. something tells me there might be reasonable formulas that might not improve Rafa's ranking because the gap between him and the top 4 might be too great, depending on how he and Ferrer perform in the next few weeks. Therefore, as we know, the tournament will just wait until nearer the RG draw, so that they can produce a formula that gives them the result that they desire, or else will just flat out admit that they have decided by committee.
Another problem is the player concerned has lost his ranking because he has missed over half a season. Protected rankings exist only for the purposes of tournament entry lists, not for seeding purposes. Other players coming back from injury are not accorded any special treatment, so why should an exception be made for Rafael Nadal?
The overall point is that if any change to the seeding process is to be made, it should be agreed upon well in advance, preferably 12 months or more in advance, in order to avoid the impression/reality that tournaments would just like to pick and choose the draws for themselves, in order to maximise what they see as their commercial interests.
The commercial aspects of the game should follow on from the organisation of a fair sporting contest. It is corrupt and ultimately counterproductive to mess around with the sport in the search for better short-term commercial outcomes.