UNLESS YOU'RE thinking in financial terms, 1979 was not a theatrical annus mirabilis. It was almost a year to forget.

True, grosses were up, most Broadway houses were lighted and theaters across the country were breaking records.But they came from either continuing trivia or revivals or works far superior to most recent efforts.

Creativity, the juice of the future, was at a despertely low level. True, the public scene, climaxing with the barbarism in Iran, dwarfed dramatic imagination. Introspection, the plague of the century, continued to infect the dramatic body.

Of the hundred-odd productions to which curiosity led me, I found four of impressive creativity. These held the mirror up to nature, affording original or expressively true viewpoints that made theater rewarding.

The most striking is "Evita," pressing the musical form beyond previous bounds. Stemming from life, it is a creation achieved through many finely joined talents. Using Argentina's Peron era, which occurred before they were born, England's Tim Rice and Andrew Lloyd Webber created a two-disc cantata of sophisticated flavors. Onto this Harold Prince welded harsh stage action of assured imagination.

In his staging Prince pursued an undertone that achieves dominion over the ostensible biography of Ena Peron so that "Evita" actually becomes a comment on our era's overriding force, the power of the media.

"Strider: The Story of a Horse" has made it from off-Broadway to the mainstream's Helen Hayes Theatre, a highly merited three-block trip.

This also imaginatively weaves together such aspects as words, music, mime and theatrical economies into a seamless, creative whole. The source is a story by Leo Tolstoy, created for the Soviet stage by Mark Rozovsky and transferred for America by Robert Kalfin, Steve Brown and Lynne Gannaway. Kalfin's Chelsea Theater Center associates clearly are artists of diversity, and the impressive company is led by Gerald Hiken, whose title performance takes us into the inner thoughts of the regretful piebald, a performance of sly understatement.

"Death and the King's Horseman," created by Nigeria's Wole Soyinka and staged by the Goodman Theater of Chicago, gave the Kennedy Center's new Terrace Theater its most impressive visitor. At first the exposition seemed to have all the steam of a turtle, but its gathering impact was haunting.

For, it developed, Soyinka was merely using an incident of colonialism to express metaphysical aspects of his culture, the intermingling of the worlds of the dead, the living and the unborn.

In the matter of performance, the author directing, the Goodman's American cast was effective for its grasp of the unfamiliar style, unfolding to reveal an attitude toward dramatic projection of fascinating depths and eddies.

The enduring vitality of the well-crafted play was revealed in Ernest Thompson's "On Golden Pond," which achieved the exceptional: three New York productions during a single year. Actor-turned-playwright Thompson showed immediate assurance in making the familiar interesting and revealing, exposing his characters through freshly heard dialogue.

A new production begins in Los Angeles next month starring Julie Harris under George Schaefer's direction, and the play already has had admired productions in Europe, Africa and South America. It introduced a young dramatist who, I am confident, will spend a lifetime creating perceptive works for international stages.

Some developments during the year were less encouraging. The Pulitzer went to another of Sam Shepard's aberrations, "Buried Child," indicating that quirkness is still preferred over substance by the New York taste-makers.

New York's off and off-off Broadway movement is even further from what it once promised. Real estate shackles all but the most ingenious institutions. Still on hold is Richmond Crinkley's imaginative plan to reactivate drama in Lincoln Center, a real estate elephant of vast proportions.

But institutional theater -- when headed by a decisive dictator, a necessary element in such undertakings -- continues its impressive search for new works. I've this year seen new works in Chicago, Louisville, Dallas, Seattle, San Francisco, Anchorage, Baltimore and Los Angeles. A few transplanted to New York did score -- most notably, Marsha Norman's "Getting Out," from the Actors Theater of Louisville. But such as "Zoot Suit," from Los Angeles, and "G. R. Point," via Baltimore, deserved more than they received in the theatrical capital.

Each year brings the passing of notable talents, but there was one this year that was more than that: the death of Preston Jones at 42, when he had his most creative years ahead of him.

In the area of government and the arts there was more than the usual scuffling between what is envisioned and what is decreed. In the populism of politics, elitism is a dirty word. In the discipline of the arts, elitism is the sine qua non.

The Kennedy Center continues to be attacked for not doing what it is not equipped to do and the downgrading of Martin Feinstein is a blow from which the center will be years in recovering

One is more amused than impressed by Joseph Papp's drum-rolling for a Kennedy Center company since this was one of Roger L. Stevens' earliest plans. One also must chuckle over the presumed novelty of realism in "The Art of Dining," Papp's first KC venture. At the turn of the 20th century, David Belasco startled theater goers with the sight of a man -- to accompany olfactory titillations -- tossing flapjacks in a Child's restaurant.

After years of foot-dragging, the D. C. Arts Council just may have moved into action. Last month's grant announcements give hope that under Peggy Cooper's drive this mishandled office may come to life.

There is some hope in the National's announcement that it has invited the Schubert Organization to be responsible for its bookings, thought that still is not completely settled.

It reminds me of Oliver Carr's little gesture on 15th Street opposite the Treasury. The facade of Keith's is still there, but its auditorium, commodious basement level and stage are a heap of rubble.

That facade symbolizes our theater of 1979. It looks impressive, but don't get too close.