Castro said nothing about how a young civilian from outside his family could lead the socialist nation that he and his older brother Fidel created from scratch and ruled with total control for nearly 60 years.
Exiles in Miami said Diaz-Canel would be a figurehead for continued Castro dominance. Cubans on the island speculated about a weak president sharing power with the head of the communist party, or maybe a newly created post of prime minister. No one who knew was talking. And no one who was talking knew.
The first clues to the mystery of Cuba's future power structure were revealed Thursday when Raul Castro handed the presidency to Diaz-Canel, who took office shortly after 9 a.m. when the 604-member National Assembly said 603 of its members had approved the 57-year-old as the sole official candidate for the top government position.
With Castro watching from the audience, Diaz-Canel made clear that for the moment he would defer to the man who founded the Cuban communist system along with his brother. Diaz-Canel said he would retain Castro's Cabinet through at least July, when the National Assembly meets again.
"I confirm to this assembly that Raul Castro, as first secretary of the Communist Party, will lead the decisions about the future of the country," Diaz-Canel said. "Cuba needs him, providing ideas and proposals for the revolutionary cause, orienting and alerting us about any error or deficiency, teaching us, and always ready to confront imperialism."
Perhaps more importantly, Castro's 90-minute valedictory speech offered his first clear plan for a president whom Castro seemed to envision as the heir to near-total control of the country's political system, which in turn dominates virtually every aspect of life in Cuba. Castro said he foresees the white-haired electronics engineer serving two five-year terms as leader of the Cuban government, and taking the helm of the Communist Party, the country's ultimate authority, also for two five-year terms, when Castro leaves the powerful position in 2021.
"From that point on, I will be just another soldier defending this revolution," Castro said. The 86-year-old general broke frequently from his prepared remarks to joke and banter with officials on the dais in the National Assembly, saying he looked forward to having more time to travel the country.
State media struck a similar valedictory tone. The evening newscast played black-and-white footage of Castro as a young revolutionary, with the soundtrack of "The Last Mambi" a song that bids farewell to Castro as a public figure and was written by Raul Torres, a singer who composed a similar homage to Fidel Castro after the revolutionary leader's death in 2016.
The plan laid out by Raul Castro on Thursday would leave Diaz-Canel as the dominant figure in Cuban politics until 2031. "The same thing we're doing with him, he'll have to do with his successor," Castro said. "When his 10 years of service as president of the Council of State and Council of Ministers are over, he'll have three years as first secretary in order to facilitate the transition. This will help us avoid mistakes by his successor, until (Diaz-Canel) retires to take care of the grandchildren he will have then, if he doesn't have them already, or his great-grandchildren."
Diaz-Canel pledged that his priority would be preserving Cuba's communist system while gradually reforming the economy and making the government more responsive to the people. "There's no space here for a transition that ignores or destroys the legacy of so many years of struggle," Diaz-Canel said.
Diaz-Canel said he would work to implement a long-term plan laid out by the National Assembly and Communist Party that would continue allowing the limited growth of private enterprises like restaurants and taxis, while leaving the economy's most important sectors such as energy, mining, telecommunications, medical services and rum- and cigar-production in the hands of the state.
"The people have given this assembly the mandate to provide continuity to the Cuban Revolution during a crucial, historic moment that will be defined by all that we achieve in the advance of the modernization of our social and economic model," Diaz-Canel said.
Cubans said they expected their new president to deliver improvements to the island's economy, which remains stagnant and dominated by inefficient, unproductive state-run enterprises that are unable to provide salaries high enough to cover basic needs. The average monthly pay for state workers is roughly $30 a month.
"I hope that Diaz-Canel brings prosperity," said Richard Perez, a souvenir salesman in Old Havana. "I want to see changes, above all economic changes allowing people to have their own businesses, without the state in charge of so many things."
But in Miami, Cuban-Americans said they didn't expect much from Diaz-Canel. "It's a cosmetic change," said Wilfredo Allen, a 66-year-old lawyer who left Cuba two years after the Castros' 1959 revolution. "The reality is that Raul Castro is still controlling the Communist Party. We are very far from having a democratic Cuba."
After formally taking over from his older brother Fidel in 2008, Raul Castro launched a series of reforms that led to a rapid expansion of Cuba's private sector and burgeoning use of cellphones and the internet. Cuba today has a vibrant real estate market and one of the world's fastest-growing airports. Tourism numbers have more than doubled since Castro and President Barack Obama re-established diplomatic relations in 2015, making Cuba a destination for nearly 5 million visitors a year, despite a plunge in relations under the Trump administration.
Castro's moves to open the economy even further have largely been frozen or reversed as soon as they began to generate conspicuous displays of wealth by the new entrepreneurial class in a country officially dedicated to equality among its citizens. Foreign investment remains anemic and the island's infrastructure is falling deeper into disrepair. The election of President Donald Trump dashed dreams of detente with the U.S., and after two decades of getting Venezuelan subsidies totaling more than $6 billion a year, Cuba's patron has collapsed economically, with no replacement in the wings.
Castro's inability or unwillingness to fix Cuba's structural problems with deep and wide-ranging reforms has many wondering how a successor without Castro's founding-father credentials will manage the country over the next five or 10 years.
"I want the country to advance," said Susel Calzado, a 61-year-old economics professor. "We already have a plan laid out." At the U.S. State Department, spokeswoman Heather Nauert expressed disappointment at the handover, saying Cuban citizens "had no real power to affect the outcome" of what she called the "undemocratic transition" that brought Diaz-Canal to the presidency.
Vice President Mike Pence tweeted at Castro that the U.S. won't rest until Cuba "has free & fair elections, political prisoners are released & the people of Cuba are finally free!" Diaz-Canel first gained prominence in Villa Clara province as the top Communist Party official, a post equivalent to governor. People there describe him as a hard-working, modest-living technocrat dedicated to improving public services. He became higher education minister in 2009 before moving into the vice presidency.
In a video of a Communist Party meeting that inexplicably leaked to the public last year, Diaz-Canel expressed a series of orthodox positions that included somberly pledging to shutter some independent media and labeling some European embassies as outposts of foreign subversion.
But he has also defended academics and bloggers who became targets of hard-liners, leading some to describe him a potential advocate for greater openness in a system intolerant of virtually any criticism or dissent.
International observers and Cubans alike will be scrutinizing every move he makes in coming days and weeks.
Associated Press writer Ben Fox contributed to this report.