OH, so Iger picked him initially, then when time came, basically said "Nah, guess we better extend my time and look outside." But that still doesn't mean it was the board that passed him over.
You're assigning too much power to Iger individually in this process. The article you quoted even mentioned this:
In any event, in the following weeks board discussions about Mr. Staggs’s future intensified. Unknown to Mr. Staggs, some on the board had resisted naming him chief operating officer the year before, but Mr. Iger had prevailed. Those reservations surfaced again periodically, focusing on whether Mr. Staggs was the ideal person to lead Disney over the next 10 years, a period likely to take the company into the uncharted waters of the continuing digital revolution and the post-cable era.
Additionally:
Sanford C. Bernstein analyst Todd Juenger summarized “our understanding of what transpired” in his report.
“The board wanted to broaden their search of potential candidates to replace Mr. Iger as CEO when his contract expires in 2018. (Mr. Iger’s contract has already been extended once, from 2016 to 2018). The board was not in a position to provide reassurance to Mr. Staggs that he would get the job. Hence, Mr. Staggs decided it was time to move on. We have no reason to believe there was any specific project failure or decision(s) that triggered this decision.”
Juenger also echoed surprised peers, writing: “Having formerly served ably as CFO, Mr. Staggs was well-liked by investors, and every indication is that he was well-liked within the Disney rank-and-file as well. Which on one hand shows the enormity of this decision for the board. The path of least resistance was clearly to ascend Mr. Staggs to CEO upon Mr. Iger’s retirement. No one would have complained or accused the board of not serving the interests of shareholders.”
“This unexpected executive shuffle likely creates stress lines in the image of cool stability that has been the public veneer of Disney under current CEO Bob Iger,” says one Wall Street…
www.hollywoodreporter.com
There was definite indecision in grooming Staggs for seven years, but from Iger inviting him back now (and apparently he accepted it) it doesn't seem that the beef was really on Iger's side. It does make logical sense that someone (or someones) on the board objected to hiring an internal candidate again, since they were sued for hiring Iger before.