WEST BERLIN -- When President Reagan delivers a major address on East-West relations Friday at the Brandenburg Gate, he is expected to echo the themes of German freedom and peaceful reunification cited by John F. Kennedy in his famous "Ich bin ein Berliner" speech here nearly a quarter century ago.

When Kennedy visited West Berlin in 1963, both German states were largely perceived as front-line surrogates in the Cold War confrontation between Moscow and Washington. But Reagan's appearance will occur at a time when Bonn and East Berlin are pressing their own priorities in ways that suggest some drifting away from their superpower patrons.

While the postwar security of Europe remains firmly rooted in the East-West division symbolized by the Wall splitting this city, the bonds between the superpowers and their allies appear to be weakening. In the view of analysts and politicians interviewed on both sides of the Wall, Washington and Moscow are asking their affluent German partners to bear greater military and economic responsibilities in their blocs.

The growing economic clout and continuing strategic importance of the two Germanys have contributed to the emergence of a more assertive Central European identity imbued with the desire to surmount tensions between the superpowers and improve trade and human contacts among neighboring states.

While Washington and Bonn have passed through various conflicts with their relationship intact, members of a German generation born after the war are moving into positions of power believing they have become innocent victims or "hostages" of the East-West division in Europe.

But perhaps the most important new factor shaping historical forces in Central Europe is East Germany's emergence as the strongest and most self-confident member of the Soviet Bloc.

"The U.S. and Soviet Union had much greater control when they played leading roles in building up the economies and societies of their allies after the war," said Gerwin Schweiger of East Germany's Institute for International Relations. "Now that those countries have matured, they are more inclined to speak out on their own."

The restlessness with bloc allegiances in both Germanys has stirred powerful if dormant yearnings for German reunification. Yet pragmatism still outweighs romanticism, and leaders in both Germanys scrupulously avoid talk of national unity. They speak instead of the German "community of responsibility" to assuage superpower tensions and prevent war from breaking out again on German soil.

"We find ourselves in the same situation," explained East Germany's deputy foreign minister, Kurt Nier. "Both German states must form policy based on the question of how to live next to each other in peace while seeking cooperative solutions to our problems."

This mutual perception in Central Europe of how to cope with life between the superpowers flourished in the wake of the 1983 Euromissile crisis. East and West Germany vowed to "limit the damage" when the Soviet Union broke off arms control talks following the West's installation of Pershing II and cruise nuclear missiles to counter the Soviet SS20 arsenal.

Now that the United States and the Soviet Union are close to an accord that may eliminate their medium-range nuclear missiles in Europe, Chancellor Helmut Kohl is striving to block momentum toward abolition of nuclear weapons in Europe, saying that would leave West Germany more vulnerable to the military threat posed by Soviet conventional forces.

For weeks, Kohl and conservative members of his Christian Democratic Party argued that abolishing superpower missiles with a range above 300 miles would confine to German territory any future conflict in which battlefield nuclear weapons were used.

Under pressure from the United States and other allies, Kohl's party accepted scrapping of American and Soviet missiles with ranges above 300 miles if West Germany could keep its 72 Pershing IA missiles that use American nuclear warheads.

While the decision appeared to be a cave-in to the western allies, West German officials insisted that the overriding reason was the support for that view by Kohl's coalition partners, the Free Democrats, and the widespread public support in the country for a nuclear arms deal.

"It would be a grave mistake to read this action as bowing solely to U.S. wishes," said a senior West German official. "We recognized how much our own people wanted this agreement. But from now on, you are going to see a government in Bonn that is much more active in promoting its own defense interests."

Kohl's prime concern now is stopping Gorbachev's arms control initiatives from extending to troop cuts in both alliances that could set a precedent for a gradual American military withdrawal from West Germany.

That prospect is so unsettling that in the wake of the bitter concession to adopt the "double-zero" position, a Christian Democratic member of parliament submitted a bill proposing that Kohl's government begin discussions with Moscow to make alternative security arrangments in preparation for the ultimate departure of U.S. forces.

For East German leader Erich Honecker, the challenge from Moscow is not so much a concern about too little security but rather the revolutionary implications of Mikhail Gorbachev's far-reaching reform program.

Honecker, who has held power for 13 years, has not flinched from publicizing his views that the Soviet leader's ideas hold little relevance for his country.

The communist authorities in East Berlin say they have managed central planning well enough to establish the highest living standard in the East Bloc and do not feel the need for market-oriented incentives to invigorate their economy.

"If your neighbor put up new wallpaper in his apartment, would you feel obliged to do the same in your apartment as well?" asked Kurt Hager, the East German Politburo member in charge of ideology, in an interview with the West German weekly Stern.

East Germany's resistance to the Soviet initiatives may also be due to Honecker's vanity, in the view of East Bloc analysts. But his rejection of Gorbachev's ideas would not have been stated so forcefully in public without evidence of a continuing power struggle in the Kremlin, these analysts say.

"If Gorbachev was fully in control, Honecker would have to toe the line," said Harry Maier, an East German political scientist who emigrated to the West last year. "Since Gorbachev is now so worried about domestic critics, Honecker can get away with just about anything short of saying he is in favor of German reunification or pulling out of the Warsaw Pact."

A more perplexing issue, according to East German party officials and analysts, is how to cope with the public yearning for greater freedom of speech and movement as Gorbachev proceeds with his campaign of openness in Soviet society.

East German officials said that within the communist party there is growing pressure from younger members to allow greater latitude in speech and travel. But the elder party leaders are concerned that a whiff of more freedom could unleash pent-up forces for sweeping democratic change that would challenge the legitimacy of the regime.

But Honecker appears to recognize the importance of measured reforms to keep public discontent from reaching volatile levels. In answer to rising criticism over obstacles to foreign travel, Honecker approved a big increase last year in the number of people permitted to travel.

More than half a million East Germans were granted visas, according to West German officials. In spite of fears within the East German government that many would seize the opportunity to stay in the West, 99 percent returned. This year, Bonn officials say, the number of East Germans allowed to travel is expected to exceed 900,000.