One generally accepted, but debatable "truism" of DC lore is that COIE had minimal or no impact on the mythos of THE FLASH. True, Pre-COIE Jay Garrick hailed from Earth-Two and Post-COIE, from the past of the Post-COIE combined Earth, but the characterizations of the various Flashes is generally treated as consistent between the Pre-COIE and Post-COIE continuities.
Upon closer examination, however, that general view is not accurate, particularly as pertains to the parents of Wally West.
When Rudolph (originally "Bob") West and his wife Mary were introduced during the Silver Age, they were stereotypical model parents of 1950s white America. Rudolph West could very well have been Ward Cleaver and Mary, June Cleaver (which I guess would make Wally West, Wally Cleaver). We saw very little of Wally's parents during the Pre-COIE period, but the glimpses we got of them portrayed them as exemplary parents by the standards of the time.
Flash forward a few decades to the 1980s and 1990s, when Wally was the reigning Flash of the Post-COIE DC Universe. Rudolph and Mary were COMPLETELY remodeled as characters...in terms of appearance, histories, attitudes, and behaviors. Nobody could mistake the Post-COIE versions of Rudolph and Mary for their Pre-COIE counterparts; the contrast between the two versions was at least as radical as the difference between Mort Weiseigner's Jor-El and Lara and John Byrne's versions of those characters.
Only a continuity retcon could explain Rudolph and Mary West's radically different portrayals Pre-COIE vs. Post-COIE, as the changes were too drastic to be explained away through character development or revealing layers that had previously been concealed. Naturally, this had a significant impact on how Wally was portrayed during the 1980s-2000s vis a vis his portrayal during the Silver and Bronze Ages. The Pre-COIE Rudolph and Mary West are unlikely to have raised the Wally we saw between 1986 and 2011, and the Post-COIE Rudolph and Mary would not have raised the Wally seen in the comics published between 1960 and 1985.
Buried Alien (The Fastest Post Alive!)