Considering the quagmire in Korea and 20 straight years of Democratic rule, a Stevenson presidency is unlikely unless the GOP nominates Taft, and the Dems are able to paint him as too conservative.
But assuming a Stevenson victory, I don't see much done on civil rights. He was pretty moderate on that issue. He was also a Cold War liberal, so he may have been more hawkish and less willing to cut Defense than Ike did.
The handling of the Suez Crisis might be one of the major differences.
Domestically again, I don't see massive New Deal programs.