The viewers who have seldom or never visited Southfork Ranch, headquarters of the Ewing dynasty, and who were attracted by all the hoopla to last night's show, may have wondered what incited such fuss. As a piece of entertainment, the drama was simplistic, trite and plodding. If this was a suspense thriller, then "Three's Company" is Kabuki Theater.

Clues, and red herrings, were dropped for weeks regarding J.R.'s attacker, and they continued last night almost to the bitter end. "I really don't think I could have shot my husband," Sue Ellen said two minutes into the show. But she didn't sound certain. Since she had more motive than anyone else and her fingerprints were on the gun, it was obvious she could be ruled out as a suspect.

Later she told the creepy Cliff Barnes that she hated J.R. so much "I wanted to kill him." and Cliff said, "So did I. So did half the people in Dallas." He meant the city, not the series.

Many more people probably concerned themselves with the shooting of J.R. than showed any interest in last week's history-making sightings of Saturn by America's Voyager spacecraft. This proves nothing of course, but it's not the most encouraging thing in the world.

Considering the intense interest so cunningly stirred up over the outcome of the show, the program itself seemed curiously casual and given to digression. There were scenes that had nothing to do with the shooting of J.R., including meetings between subsidiary characters and more of the show's corporate intrigues, its least tantalizing feature.

Kristin's guilt was widely suspected partly because it was known that Mary Crosby who plays the part will leave the series after a few episodes this season. That seems to rule out the possibility of a trial that would drag on for several Nielsen weeks. J.R. swore last night he would handle the matter in his own way, which means something oily and devious is in the works.

In Hollywood, Larry Hagman, who plays J.R., arrived at Chasens to join the cast and CBS executives for a "Dallas" party. Wearing a cowboy hat featuring a large feather, Hagman ran up the steps to plant a kiss on Crosby. f

"It came as a surprise to me," said Crosby, daughter of the late Bing Crosby. "We shot four endings but I had a pretty good idea Kristin was the guilty one because I had been written out of the show for the last four weeks."

Hagman said, "Kristin will be going to California but I'm not going to tell you what becomes of her because that's part of the continuing suspense of 'Dallas.'

"I'm sure as hell glad this thing is over and I hope it's a long time before somebody takes a shot at old J.R.," he said.

Ratings for "Dallas" have been increasing as the announcement of the culprit grew nearer. Even "Dallas" reruns have been slaughtering first-run competition on other networks. Last night's episode, by no accident whatsoever, fell during a crucial "sweep" month, when ratings data help determine ad rates that a network will charge in the future.

"Dallas" may in fact prove the pivotal element in winning the current season for CBS and returning the network to the No. 1 spot it occupied for 20 years until ABC stole the title in the mid-'70s.

Apparently there's nothing like a good attempted murder to bring the nation together. Last night's "Dallas" was the most eagerly awaited series episode since the Ricardos had a baby nearly 30 years ago on "I Love Lucy," and it was expected to overtake the previous ratings for a series episode set by the finale to ABC's "The Fugitive" in 1967 when 45.9 of all U.S. TV homes tuned in to watch David Janssen catch the one-armed man who had eluded him for three seasons on the air.

In England, where "Dallas" has also become a national obsession, the episode won't be shown until tonight, but radio stations planned to broadcast the name of the culprit at 4 a.m. London time, immediately after word leaks out to 80 or 90 million people.

Passengers on Air France flights to Europe were to be told who shot J.R. by the pilot as soon as the news was known, spokesmen said. An airline dispatcher was to watch the program on the air and then radio the news to all captains on transatlantic flights. Braniff Airlines, headquartered in Dallas, also planned to beam the news to all its airborne crews and passengers.

Riding the crest of "Dallas" hype with glee, Hagman recently posed for a J.R. Ewing wax figure while in London. He stood on a bronze plaque made from one square foot of Southfork, the real Texas ranch that portrays the Ewing spread on T.V. Joe R. Duncan, the land developer who owns the ranch and has been called "The Real J.R.," recently began selling foot-square parcels of the land for $25 each.

Duncan told a reporter the land is going like designer jeans. "Everyone wants one as a gift for somebody," he says. He wouldn't say how many little lotties he had sold, and that wasn't all he wouldn't say. "There's two things I'm not ever going to reveal. What Lorimar Productions pays me for the for filming at Southfork, and how many lots we've sold." As many as 2,000 tourists come by Southfork to see it for themselves and take pictures on weekends, Duncan says.

Clearly, things had gotten OUT OF HAND. Even the State Department was part of the frenzy. Spokesman John Trattner told a reporter he'd received inquiries at State about the J.R. matter and issued a statement saying "I would like to reiterate our long-standing policy against acts of terrorism."

The State Department has "nothing official to report" on the J.R. affair, Trattner said. Is everybody nuts? Just about.