The way I see it, realistically, in case Blizzard decides to move forward and sue in an extreme situation, it would be for tortious interference with contract. Reposting what Xinhuan already mentioned, over at the WoWAce forums :
In order to establish tortious interference, 4 things need to be proven:
(1) A valid contractual relationship exists between X and Y,
(2) You know of this relationship,
(3) You intentionally and improperly interfered in the relationship and caused a breach or termination of the relationship, and
(4) X or Y has been damaged as a result.
We are all aware that (1) is already established because of the EULA, it would be extremely difficult for a developer to refute (2) (unless we are naive to believe that we all run and test our addons on independent sandboxes
), (3) I guess can also be easily proven, provided that the policy is already in effect and by knowingly breaching it, you intensionally interfere with the contract, so we are basically left with Blizzard having just to prove (4), which brings us to what a lot of people have already discussed to death. Unless there are technicalities or something that everyone is terribly missing, one thing is for sure. It would be unwise for a dev to outright ignore the policy, though realistically, the most probable outcome would be to just have his addon(s) blacklisted/disabled.
Other than that, the moral implications are, at the end of the day, simply a matter of opinion (and a subject also beaten to death) and imo both sides have their strong points, which is precisely why the (more reasonable part of the) community is so torn apart.