VIENNA — A YEAR ago everything seemed set for the new-look Eastern Europe. Eastern Europeans and Western observers were encouraged about the region's future.Now, as the second post-revolution year ends, things look different. The new regimes have been only modestly successful in changing the old economy to the new. Western aid remains slow and based on a disappointing number of conditions. Three signs of the gathering difficulties have appeared this month. * Poland, the avant-garde of "shock therapy" reform, is halving its big privatization program to avert worsening public disaffection. "The atmosphere is too hot," said the privatization minister, Janusz Lewandowski, in Vienna Oct. 15. "The human costs of transition are too high. We've now decided on a gradual approach." * In similar vein, Adrian Severin, the nonparty academic overseeing economic reform in the recently ousted Romanian government, at about the same time warned that without Western help the "old forces" can halt reform by exploiting grievances. * In Bulgaria, against the same background of hardship, the former communists lost an overall majority, but only narrowly, in an Oct. 13 election that all the polls indicated they would lose outright. Everywhere, initial euphoria has faded. The social costs of reform are proving higher than governments and people reckoned with. Czechoslovakian President Vaclav Havel has said that, despite the new freedom, people had become "anxious, nervous, and dismayed by the scale of the problems before them." A Czech economist has said the transfer to a market economy will take more than 20 years. Modernizing industry, environmental protection, and new infrastructure will consume at least $50 billion through the year 2000. East Europeans rejoiced at political liberation from the Soviet alliance. But they have realized more and more that economic hazards lie outside the alliance which Western economic solutions do not diminish. The failure of the Soviet economy has also dealt two shattering blows to Eastern Europe: the cuts in volume and the rise in price of Soviet oil (on which they still depend), and the virtual loss of the Soviet market for exports they cannot sell in the West. Now these conditions are likely to worsen. A recent World Bank study forecast that by the end of the century, Eastern Europeans may only regain their living standards of 1989. Governments are trapped between what is economically desirable and what is socially acceptable - between impatient public dreams of quick benefit from reform, and the wait for Western aid, which will be given only when market economies are functioning and transition is complete. All this year, East European leaders have bitterly assailed West European tardiness in granting them associate status in the European Common Market. If long term support is deferred, they say, the West could at least open its markets to Eastern European exports so they can raise much needed money as well as buy the technology vital to reform. Poland's straight-talking Lech Walesa says the West is very shortsighted. "When we fought the Communists the West helped us, " he says. "Now, when it comes to helping our restructuring, it avoids responsibility. That's also careless, because disaster here will also hit the West," Mr. Walesa says. In country after country, popular consensus behind reform is crumbling. Growing nationalism plays on difficulties to widen political weaknesses. Unemployment escalates to levels older people recall as the prelude to World War II. These are all valid points the West should keep more in mind as it goes on debating - without end, it seems to East Europeans - just how and when to give a really helping hand.