America-Dwight Eisenhower. Ike represents the beginnings of America as a super power. The 1950's was a true golden age for the US. Real prosperity. Special units should include the Super Carrier, The Abrams Tank, The B-52 Bomber.
Russia-Nikita Khrushchev. The rise of Russia as a super power It was Khrushchev who told the US, after the U2 incident, "we'll kick you so hard you won't know your own name" The Soviet T-10 (Obyekt 730) Tank, Super Submarine as special units
Not going to argue Date of US Super Power Status, except to point out that by most standard measurements, the USA was already the premier industrial power in the world before WWI and the world's economic arbiter by 1918, and that the foundations for 1950s 'Superpower' status were put in place under FDR: a navy and air force larger than all the rest of the world combined, a massive strategic bomber force, nuclear weapons development, and an industrial base of mind-boggling productivity compared to any other combination of powers on earth.
But, specifically, some of the units are not appropriate.
The M1 Abrams tank was not fielded until 1979 - long after Eisenhower's administration, and even the elements of the tank were not under development until the ill-fated MBT program of the mid-1960s - also after Eisenhower. The 'tank' UU under Eisenhower would be the M60 and M60A1, the first Main Battle Tanks fielded by anyone in 1960 - 64, which took over the capabilities and tasks of all of the previous heavy and medium tanks.
The T-10 was the last Soviet heavy tank in production, going into service in 1953 and starting development in 1946 as Obyekt 705A, getting redesigned as Obyekt 730 or IS-5, IS-8, IS-9, and IS-10 before being finalized. As a late heavy tank, it was obsolete within 7 years like its contemporaries, the US M-103 and British Conqueror. A better Khruschevian Soviet tank would be the T-64 or T-64A, first developed as a prototype in 1958 as the Obyekt 430 and entering service in 1966 - slightly after Khruschev's removal as Premier, but the development work was all under his premiership, and the T-64 was the first Main Battle Tank in Soviet service, making all of their previous medium and heavy tanks effectively obsolete.
Another potential Khruschev-era Soviet UU would be the MiG-21 jet fighter, developed between 1954 (the initial Ye-4 design) and 1959, so entirely under Khruschev. It remains the most-produced aircraft in the world since 1953, and has been used by more air forces around the world than any other aircraft. It would tie in nicely with a Soviet Union mass production characteristic, which Civ seems to love to give Civs based on the Soviet Union and/or modern Russia even though the Soviet Union's industrialization in the 1930s was based almost entirely on American aid and production techniques.
But that's another Thread's worth of posts . . .