IT IS DEFINITELY not the "realigning" election Republicans dreamed of a year ago -- that would increase their control of Congress, smooth the way to completion of "the Reagan revolution" and establish them as the country's new majority party.

It is probably not the "repudiation of Reaganomics" that Democrats thought possible when unemployment passed 10 percent and bankruptcies mushroomed.

Two days before the voting, it looks more likely that the Halloween slogan of "trick or treat" may last until Election Day, with a mixture of good and bad news for both parties.

Democrats are likely to capture a number of governorships from the GOP and thereby strengthen their grassroots base for the 1984 election. But most indications in the final days of the campaign are that Republicans will retain control of the Senate and have a good chance to keep their conservative coalition with some southern Democrats alive in the House of Representatives.

But there are abundant cautions that voters may have some final "trick" in mind that could, once again, make the experts look foolish.

The Post's rundown, covering all Senate and governor races and the 100 or so House races with the closest contests, appears on Pages C4 and C5. CAPTION: Chart, THE HORSE RACE, by Robert Barkin -- The Washington Postreformers' attempts to dismantle them.

The other main complaint in Grabski's letter, which was dated Oct. 12 but reached Western correspondents here this week, is the inner decay of the Communist Party. He wrote that in his factory organization in Poznan, membership had shrunk almost by half since the introduction of martial law.

Grabski demanded a "revolutionary ideological purge" of the Communist Party even if it resulted in "a further drastic reduction of party membership." He said that at present the party had no firm ideological orientation since it included people of "diametrically different" political outlooks from Marxist-Leninists to Social Democrats and even Christian Democrats.

At present, it seems unlikely that the hard-liners command sufficient support on the 200-member Central Committee to force Jaruzelski out.

Analysts note, however, that Grabski has a remarkable ability to sense which way the political wind is likely to blow in the future. In May 1978, for example, he was dropped from the Central Committee after a blistering attack on then-Communist Party leader, Edward Gierek. Just two years later, Gierek fell from power and Grabski entered the Politburo in triumph.

In June 1981, Grabski called for the resignation of Stanislaw Kania, Gierek's successor, accusing him of being too soft on Solidarity. Kania deflected the attack and, in the short term, it was Grabski who lost out. Four months later, however, Kania was forced to resign.

Justifying his present stand, Grabski said his opinions and warnings had always been considered "premature" in the past -- but had been proven true ultimately.