"Here we are in 1978 trying to negotiate an agreement formulated in 1973 that might take place in the 1980."

The words are those of a somewhat cynical Western delegate to the 16th round of talks between Western and Soviet bloc military alliances on reducing troop strength in Central Europe that opened here yesterday.

His remarks reflect an underlying sentiment among some Western delegates that the discussions have taken on a certain air of unreality. The feeling is that so much has changed in the world since these talks got under way that a new hard look at their basis, direction and prospects for ultimate success should be taken.

This is a minority view but it is an important undercurrent. Virtually all Western delegates privately acknowledge that there is some validity to it, though most do not see any other course to take.

The East-West mutual and balanced force reduction (MBFR) talks began here in October, 1973, with the official Western objective of reducing the heavy numerical superiority of Warsaw pact forces in Central Europe and thereby, it was hoped, reducing the chance of war by eventually cutting the forces of both sides to a smaller joint level.

Unofficially, however, it is widely acknowledged that a big part of the Western push to get these talks started was a Nixon administration effort to prevent acceptance by Congress of a barrage of amendments by former senator Mike Mansfield in the early 1970s calling for unilateral U.S. troop cuts with the Warsaw pact, pressure for the Mansfield proposals could be reduced on Capitol Hill. The strategy worked.

Now, however, times have changed dramatically.

With the Vietnam war over, not only is there no significant pressure from Congress to bring American soldiers home from Western Europe, there seems to be increased congressional support for beefing up those forces as attention on U.S. defenses swings back to Europe.

The attention of the U.S. military has also shifted back to Europe.

"It's the only front we've got left," said one military official.

A new NATO long-term defense plan has just been approved to build up equipment further. And if progress is not made soon in these talks, the momentum of that project as ti gets into its buying and shipping phases might be hard to stop, officials here acknowledge.

A new array of Soviet medium-range missiles and bombers targeted on Western Europe has been deployed in recent years, prompting top West German defense officials to suggest publicly that these talks may soon become obsolete if progress doesn't come soon.

Whether the United States would want to pull several thousand troops out of West Germany now, and whether West Germany would want to deal with the political repercussions of such a pullout even under an agreement with the East, also may not have been thought through, some officials believe.

In January, the French government proposed a different forum of European disarmament conference that would encompass "the Atlantic to the Urals," a reference to the Western sections of the Soviet Union. This is a far broader geographical region than the current MBFR talks, which are focused on Central Europe.

This proposal, even though frowned upon by Washington and seen as possibly disruptive of the current talks, has some appeal to the West Germans who would like to see Russian troops roll much farther back toward the east if some U.S. troops go back across the ocean.

The Germans, though solid supporters of the current talks, are worried about Central Europe becoming some sort of specially controlled areas of the world as a result of MBFR. West Germany would be the main country whose territory and armed forces would come totally within that framework. This explains why the Western position in the MBFR talks has been to oppose flatly any specific ceiling on the West German forces within any common ceiling reached by the two alliances.

A major goal of the Warsaw Pact in these talks has been to try to force national ceilings on specific countries, especially the Germans, since Bonn's army is the only one that could expand quickly in an emergency.