After the rumours surrounding Neil Blomkamp earlier his week, it appears that Peter Jackson is once again back as the favourite choice to take over directorial duties on The Hobbit. The Hollywood Reporter suggests that Jackson and the studio reps are in deep discussions over the possibility. Jackson will likely only accept if guarantees are given that filming can start as soon as possible to ensure the films are released in 2012 and 2013. Jackson is developing several other projects, including working on the Tintin movie trilogy with Steven Spielberg and developing Naomi Novik's Temeraire series (possibly a television series), and doesn't want to indefinitely delay them whilst working on The Hobbit (similar to the concerns that Guillermo Del Toro expressed, leading to his departure from the project).
Despite Jackson's reluctance to compete with his prior work in Middle-earth, there are rising complications that make hiring another director difficult. Payment for the director of the movies is likely to be much lower than is usual for a top-line director, due to the complex number of studios, interests and producers involved in the project. In addition, an incoming director would likely have very little creative control over several key aspects of the project, such as the visual design and script, which have already been extensively developed by Jackson and Guillermo Del Toro. A big-name director would like balk at not being able to make their own decisions in these areas.
Apparently the next few days will be crucial to decide if Jackson will direct and, if not, what the ultimate fate of the movies will be.