At the Metropolitan Opera this month, the bass-baritone Bryn Terfel, a singer acclaimed particularly for his comic flair, is singing the role of Wotan, a ne plus ultra for his voice type. On Friday night, James Morris, a world-renowned Wotan, made his Washington National Opera debut in his first-ever outing in the comic title role of Donizetti’s “Don Pasquale.” You might say it’s an unusual switch, effectively casting both men against type. Having seen both performances now, I heartily wish they would switch back.

With this “Pasquale,” WNO limped to the end of an up-and-down season in which the appointment of a new music director, Philippe Auguin, was overshadowed by the announcement that Placido Domingo would be stepping down as general manager and the company would merge its operations with the Kennedy Center. This opera was planned long before those announcements; nonetheless, the intention was doubtless to close the year on a light, sparkling note, with what is arguably Donizetti’s musically richest opera. WNO could gain attention by presenting Morris for the first time in a way that nobody had ever seen him before, with Domingo himself in the pit.

Whatever the actual thinking behind this “Pasquale,” the result, alas, was less sparkling than leaden. The problem started with Leon Major’s production. Allen Moyer’s 17th-century costumes (imported from Glimmerglass and the New York City Opera) added layers of unnecessary frills. And Major shoveled on comedic shtick to match, with plenty of heavy-handed, summer-stock gestures capped off by a chorus prone to flailing around helplessly with feather-dusters (they played Pasquale’s servants) or sticking their heads out of windows to gawk at the action.

Yet, in an opera driven by the strong personalities of its four leading characters, the character direction was so subtle that all four remained silhouettes without much personality at all. Major has just published a book on opera acting, “The Empty Voice,” that points out accurately how seldom it is done well; unfortunately, he wasn’t able to show, here, how to do it right.

It was all too clear that Morris was playing against type. Don Pasquale is both a comic and a poignant figure, a man in his 70s who decides to marry to spite his nephew Ernesto, and is taught a lesson when the young wife he thinks he is marrying (actually Ernesto’s beloved Norina, masquerading as the sister of Pasquale’s house physician, Dr. Malatesta) turns out to be a bossy shrew who spends his money on new servants, clothes and furniture. By the end of the evening, Pasquale is all too relieved to discover that the whole thing has been a fiction designed to teach him a lesson.

Morris, 64, is known as a singer of heroic stature with a heroic voice, but he didn’t show much of either in this part, although he tried gamely to muster some standard comedic gestures. And his singing was so muted that it was sometimes hard to hear him at all.

Domingo, unfortunately, didn’t help. It wasn’t for lack of trying. He worked with tremendous earnestness and a lot of energy from the very first bars, attempting to shape the score by slowing phrases down and speeding them up to maximize effect — but approaching this musically wise comedy as if it were a Puccini opera, passionate and highly dramatic.

Watching him working his heart out in the pit, giving it his all, but drowning out the singers and leaving ensemble sections adrift in the process, I realized that Domingo conducts much as he sings: with ardor, complete commitment, slightly overdone gestures and an involuntary tendency to focus attention on himself. These are all great qualities in a leading tenor, but they aren’t so great in a conductor, particularly in an opera that calls for a light touch and an adroitness with ensembles.

Norina is one of Italian opera’s quintessential heroines, able to turn a man’s head, wrap him around her little finger (Major’s production actually casts her as an actress) and leave everyone loving her in the end as she tosses off artless cascades of notes. Ekaterina Siurina, a Russian soprano who has sung a few times at the Met, did almost none of these things in an unimpressive WNO debut; she hit the notes and struck some charming poses, like a talented student.

By contrast, the Spanish tenor Antonio Gandia, as Ernesto, made a considerable impression. At first, his sounded like just another slightly pushed, smallish, hard-edged tenor voice, but he proved to sing with flexibility and considerable push on the top notes, delivering the tenor goods with a lot more power than it initially seemed he had in him.

Dr. Malatesta is a Figaro-like character, the baritone who comes up with a crafty plan and steers it to a successful conclusion. Dwayne Croft has earned his stripes in this field simply by being reliable; he wasn’t particularly funny, but he got the job done.

In Act 3, Pasquale and Malatesta have a rollicking patter duet that involves passages of singing at what seems faster than the speed of sound. Morris, at least, was almost totally inaudible, but the segment nonetheless got warm applause and its traditional encore. The motions, in short, were observed. It all added up to a lackluster ending to a season that, all things considered, WNO might well prefer to forget.