With the Tony nominations closing two weeks from tonight, the Broadway opening schedule is filling up. By Tony award night, June 7, the season may look a trifle more productive.

There's irony here, for when success does strike, the hits now run for years, depriving incoming hopefuls of desirable stages. It's true that financially theatrical trade never has been heavier, but it's also true, as Variety recently observed, that this has been "a terrible season for American plays."

This is one reason why tonight's Lincoln Center opening of Woody Allen's "The Floating Light Bulb" could be critical, not only for Allen, who's lately confined himself to film, but also for the Vivian Beaumont Theater.

After Joe Papp washed his hands of that tricky stage, producer Richmond Crinkley came up with a plan involving celebrities in unfamiliar assignments. The first, the revival of Philip Barry's "The Philadelphia Story," was viewed with disdain for the awkwardness of its setting and direction. The second, Philip Anglim's "Macbeth," laid another egg. But Allen's light bulb, starring Beatrice Arthur, Jack Weston and Danny Aiello, may still brighten the Beaumont's future.

It also could enhance the dismal record of new American plays. Since last fall such playwrights as Arthur Miller, Steven Tosich, Albert Innaurato, Sidney Michaels and James Prideaux have all had quick failures. Jean Kerr's "Lunch Hour," still running, didn't set the Hudson on fire, and Edward Albee's "Lolita" adaptation prompted the season's most scathing notices and a mere dozen performances.

This brings us to Neil Simon's latest, "Fools," vastly more fun than the major reviewers reported. Here, Simon turns his back on his usual contemporary America to give us a fairy tale set "long ago" in a Russian village whose residents are cursed with idiocy. In our enlightened age it is beneath our dignity to consider mental aberrations comical, but Simon is after more than that.

Originally titled "The Curse of Kulyenchikov," this fey piece is directed by Mike Nichols, brought in as a replacement in Boston for Gordon Davidson. The major aisle-sitters didn't cotton to Simon's change of pace and, indeed, urged Simon to "come home." Considering that the critics generally have scorned Simon wherever he's at, this must have struck him as baffling advice indeed.

With John Rubenstein heading the cast as a school master who hopes to exorcise the curse, the rest of these farceurs include Gerald Hiken, Joseph Leon, Richard B. Shull, Harold Gould, Mary Louise Wilson and Pamela $99[WORD OMITTED] tiest fruitcake of the season. If producer Emanuel Azenberg keeps it running long enough for that powerful force, "word-of-mouth," to take effect, this could become one of Simon's most produced comedies, which is saying a lot.

The surviving non-musicals are British, dominated by Peter Shaffer's "Amadeus," the sole dramatic hit of 1980-'81. Hugh Leonard's impressive, ingenious "A Life," despite Alec McGowen's name above its title, never did find its audience, and Athol Fugard's "A Lesson from Aloes" was unimpressive.

That adventurous Elizabeth McCann-Nelle Nugent producing team followed up their impressive record with two more from London, Pam Gams' "Piaf" and Andrew Davies' "Rose." Both plays are of the Mosaic School, that is, a series of apparently disjointed scenes which finally can be perceived as an overview instead of the Beginning-Middle-End school, not unlike Shakespeare. This style is again coming into fashion, but to traditionalists it is upsettingly dissheveled chaos. One finds it in Samm-Art Williams' "Home," the musical "Barnum," the impressionistic "for colored girls . . ." and an increasing number or recent works.

Having heard about its violent language and the heroine's on-stage defecation, I'd expected to find "Piaf" a shocker. Instead, I was honestly moved by this penetrating portrait of a woman brought up on the streets to whom the only reality is Now.

Gams' episodic choices detail an attitude of life outside the usual theater-goer's ken. The Parisian sparrow, risen to notoriety through a gangland murder, has absolutely no concept of anything other than the immediate moment. Each time she sang was for the instant. The fact that she knew of no other way to live her predictable tragedy is solidly rooted in this milieu Gams so joltingly reflects.

Initially produced at the Royal Shakespeare's Other Place stage in Stratford, "Piaf" has 14 players for 29 characters. Weeks after the Broadway opening, McCann-Nugent and director Howard Davies were still working on the Plymouth Theater version, finally adding the song for which Piaf was especially noted, "La Vie en Rose." Jane Lapotaire (last Monday's TV Cleopatra) is striking in the remarkable title part, a certain Tony nominee, and a close second is her London co-star, Zoe Wanamaker.

"Rose" is less impressive, but distinguished by Glenda Jackson's and Jessica Tandy's performances. In mosaic, impressionist fashion, Davies depicts an independent-minded contemporary English schoolteacher's view of her country's changing mores.

As for the season's new musicals, the most recent new hopeful is "Woman of the Year." The attraction is Lauren Bacall who, fittingly, strikes the immediate note of hope, appearing solo at stage right immediately after Don Pippin's zingingly led overture and marvellously spotlighted in a gown of shimmering gold.

This is an adaptation of the Katharine Hepburn-Spencer Tracy 1940 film which won an Oscar for its collaborators, Michael Kanin and Ring Lardner Jr. Peter Stone's book, however, is a lackluster business, recasting "Woman of the Year" from a Dorothy Thompson, heavy-thinking type to a Barbara Walters TV star and turning the sportswriter with whom she tangles into a cartoonist. Were Michael Sporn's animations more original and livelier, this device might have helped, but they're flat and uninspired. A string of ballads in Act I sung by such meager voices as Bacall's and Harry Guardino's is arid listening.

When Stone breaks from the film plot's mold in Act II, opportunities improve for the John Kander and Fred Ebb score, allowing for comedy songs for the stars and a worthy number for the vital next-to-closing spot, "The Grass Is Always Greener." Here the worldly "Woman of the Year" gets to meet her first husband's second wife, a novel plot twist. With Bacall and Marilyn Cooper singing this comical comment, "Woman of the Year" reaches its high mark and almost makes that $35 top seem worth the price.

Starring Zizi Jeanmaire in husband Roland Petit's staging, Cole Porter's 1953 "Can-Can," opening in time for the nominations, will be joining such other retreads as "Brigadoon" and "The Pirates of Penzance." Still holding over are the five other musicals plus "A Day in Hollywood."

Those exhaustive changes made while "Sophisticated Ladies" was at the Kennedy Center must have had some effect, for this Duke Ellington melange, now a revue, had a hearty New York welcome. "Copperfield," inspired by guess what Dickens novel, has a still undetermined future with the family trade, which may have been interested, or put off, by critical agreement that the devices which worked so well with "Oliver!" in other hands are employed for another Dickensenian musical. Its sets, visual effects and use of children twisted the critical memories back to that Lionel Bart creation of nearly 20 years ago.

First of the season's musicals was "42nd Street," which opened at the Winter Garden the September day its director-choreographer, Gower Champion, died. Removed to the larger Majestic on highly favored 45th Street, this is bound to rank among the favorites.

Elizabeth Taylor and "The Little Foxes" will open in time for the nominations on May 7 at the Martin Beck; it is already sold out for the run. nOther entries in time for the voting include Renee Taylor and Joseph Bologna in their own new comedy, "It Had To Be You," "Lena Horne: The Lady and Her Music," Melba Moore in "Inacent Black," "The Moony Shapiro Songbook" and a few more slipping in just under the wire.

The power of the Tonycasts has become a major force, not merely in prolonging Broadway runs but in guaranteeing national tours.

Every one of the current road attractions makes much of the silver awards in promotional material, including the National's "Children of a Lesser God," so effectively staged by the aforementioned Davidson, of the Los Angeles Mark Taper Forum. Though a film version of the character (though not of the play) has come and largely gone, three companies of "The Elephant Man" are running in their third years, and 10 touring musical productions represent five still clicking up runs of years on Broadway: "Annie," "A Chorus Line," "The Best Little Whorehouse in Texas," "Dancin'" and "They're Playing Our Song." All have won Tony awards in one category or another, and Tony producer Alexander H. Cohen can take credit for Broadway's most effective national promotion. The June 9 telecast will be extended to two hours, giving hope even that whatever regional theater wins a Tony will rate air time.

Historical note: The year's Pulitzer drama award again went to a regional product, Beth Hanley's "Crimes of the Heart," first produced by Jon Jory for the Louisville Actor's Theater New Play Festival in January 1979. Subsequently present off-Broadway, this will have a main stem production next season. Ever so gradually, the Pulitzer people are recognizing that the American theater exists outside the tight little borough of Manhattan.