So let's start off by considering the immediate impact.
The death of Mao would specifically mean mean several key policies would change, effectively butterflying the Great Leap Forward and Cultural Revolution (and almost certainly Deng's economic reforms). First, the agricultural reform debate goes in favor of Liu Shaoqi as Mao is no longer among the living, thus mechanization takes precedent over (forced) collectivization as agricultural policy, as opposed to Mao's and OTL's policy of collectivization (primarily) and, later, Mao's belief in the mass line and "walking on two legs". As Mao is not behind the wheels to put his foot down on the accelerator and drive the (at the time, prospering) economy straight into a brick wall, agricultural productivity would not take quite the same shock as it did in the 1958-1962 period. Moreover, Mao is not alive to effectively try and make war against reality at the Lushan Conference, which meant the upper party members are more likely to actually respond to the crisis, which means it is unlikely that there will be a policy-induced famine that causes some 30 million deaths by starvation with 30 million delayed births. He would not be around later to advocate for "permanent revolution" and argue that class struggle was a feature of socialist societies as well, and would not be around to criticize and undermine the new CCP bureaucracy that would culminate in the Cultural Revolution with his mass mobilization of students. These are all undeniably huge positives in the short term.
Liu Shaoqi (and his protege, Deng Xiaoping) will be the immediate inheritors of Party leadership. By this point, he was effectively appointed the #2 spot in within the party (despite Mao's own preferences and his rivalry with him) due in part to his own power base within the burgeoning bureaucracy and his effectiveness in organization and policy administration. Liu Shaoqi was Moscow-trained, and favored Soviet-style development, focusing on a command economy & "strategic" heavy industries, which is economically (for China's comparative advantages) the worst approach to take. Heavy industry is capital intensive, a high degree of technical knowledge, and good infrastructure, all of which China is severely deficient in and thus dependent on Soviet aid and, particularly, loans (which at this time was piling up in terms of debt, much to the resentment of Mao and some others in the Politburo). Liu Shaoqi is likely to continue and double down on this strategy, which while comparatively stabilizing for China in the short term is actually quite detrimental to the long-term economic development of China. Part of the impetus for the Great Leap Forward was the economic demands that Soviet loan repayments was having on Chinese finances, and thus demanded increased extraction from the peasants (land/agricultural taxes being the primary form of revenue for highly agrarian states). The GLF and the Sino-Soviet split disrupted this (with tragic human results), but staying on course as Liu Shaoqi is likely to choose will worsen this fiscal problem, which will come to a head eventually.
Without Mao, the cult of personality that bound together the nation and legitimized the CCP begins to fade; Liu Shaoqi was quite the bureaucrat and lacked the same personal charisma that Mao had, whom with my own meetings with former ambassadors who met with Mao stated that he just exuded an undeniable eccentric magnetism that drew people to listen to him. He was an old peasant revolutionary, fighting against the ossification and bureaucratization of the CCP along the Soviet model, which while pro. His political struggles with other CCP leaders utterly broke party norms, creating inter-party factionalism and promoting adherence to the state line. The aftereffects of the GLF and the Cultural Revolution meant that everyone, urban and rural, party cadres and the workers themselves, and even party leaders recognized the fundamental failings of socialism and Maoism, and would facilitate and allow for a major paradigm shift in CCP policy, leading itself to reform.
Without that impetus and drive for a radical change in direction, China is likely to continue along in the Soviet model, bureaucratized by the party proper. Meanwhile, continued frustrations with the bureaucratic machine would continue to build, until you likely see a more explosive version of the Cultural Revolution if any weakness in the state is seen. Mao did not create the movement out of nothing: there was building frustrations with the Soviet developmental model and within students and workers that was harnessed by Mao during the Cultural Revolution. I'd speculate that without Mao, China goes down the road of other Soviet-style economies and implodes during the 90s, instead of initiating reforms in the late 70s/early 80s and being able to economically reform and develop since.
In foreign policy, the Sino-Soviet split is likely to be delayed; Mao is not alive to seriously drive foreign policy, and on the Chinese end it was driven in particular due to Mao's distaste and hatred for Khrushchev, but also the secret provisions of the Sino-Soviet treaty, the mounting pressures of Soviet loans, and the leashing of China's foreign policy to Soviet interests. The neutrality of the Soviets in Indo-Chinese border clashes, or highly delayed support for China during crises during the Taiwanese Straits all exacerbated the split into open border clashes (and finally the Brezhnev doctrine made it readily apparent), but the primary split occurred during the late 50s and ruptured in the early 60s due predominantly to Mao's own personality and approach to foreign affairs. Long term, a delayed or butterflied Sino-Soviet split means that there is likely no major US rebalancing in the region as was done by Nixon/Kissinger's "opening of China". That required a prominent, "anti-communist" president well-versed in foreign affairs (and Kissinger as a force of nature as National Security Adviser), but also a receptive Chinese leader looking for allies, and a Sino-Soviet split so obvious/tangible that even the most die-hard anti-communists in the USA could look past ideology.
Sino-American rapprochement was necessary, long-term, for China's economic reforms. While China's economic "miracle" started in the countryside as decollectivization took place, creating a surge in agricultural productivity that freed up labor to go into rural Town-Village Enterprises (TVEs) and into private businesses, urban development was funded both by FDI and by the growing export-economy made possible by access to the liberal world economy as "light", labor-intensive consumer industries, long neglected by Soviet style industrialization, flourished as "low hanging fruits", readily picked up by the growing market. Again, a China ideologically and geopolitically bound to the Soviet Union would not be free to pursue market reforms, not to mention to lack of domestic receptiveness to such a reorientation of policy.
Thus, the legacy of Mao is incredibly complicated. It's very hard to disentangle China and Mao during the 1950s-early 1970s because of the sheer impact he had on shaping the country, and while the disasters under his belt are plainly obvious (the GLF in particular), in many ways he paved the way for China to undergo reform as opposed to continue along the lines of a Soviet-style economy.