(CNN) — An unprecedented lack of consensus among the guilds representing actors, directors, writers and producers has flummoxed Oscar prognosticators, with more genuine uncertainty surrounding the best picture race than is usually the case this close to Sunday's ceremony.
The changing face of the Academy of Motion Picture Arts and Sciences, which presents the awards, has further complicated the guessing game, since trying to anticipate the future based on the group's past isn't a simple task after the Academy made a concerted effort to expand and diversify its membership.
Still, there are some key races where the outcome looks pretty clear and frontrunners have definitely emerged. With that as a disclaimer, here's a rundown of what likely will win -- and what in this critic's estimation should -- in most Oscar categories heading into Sunday night's festivities, which, if form holds for the current awards season, are sure to prompt plenty of grousing whatever the outcome.
Will win: "Green Book." Should win: "Roma."
Despite considerable criticism of "Green Book" and various off-screen controversies, the fact-based historical film checks off a lot of boxes of past Oscar winners, and already has a Golden Globe and the Producers Guild's top prize under its belt.
What appear to be its principal competitors both face hurdles: "Roma," not only because it's a foreign-language film, but thanks to its release via Netflix, which continues to stubbornly withhold box-office data; and "Black Panther," which has already claimed a Screen Actors Guild Award for outstanding ensemble cast.
Both those films are deserving, but "Roma" left a deeper impression than virtually anything else this year. As for "Black Panther," given the long history of superhero movies being ignored by award shows, Marvel's breakthrough really does feel like one of those cases where the adage "It's an honor just to be nominated" applies.
Will win/should win: Rami Malek.
"Bohemian Rhapsody" wasn't a great film, but the extent to which it's a good one depends almost wholly on Malek's electric performance. Christian Bale is the stiffest competition, but "Vice" will likely have to settle for a makeup/hairstyling Oscar for the wizardry that somehow transformed the former Batman into Vice President Dick Cheney.
Will win/should win: Glenn Close
Close has marched through awards season for her role in "The Wife," and there's undeniable sentiment behind crowning her distinguished career with this seventh-time's-the-charm nomination. As for Lady Gaga, her powerful debut has to overcome that playing a rock star doesn't feel like much of a stretch, while Olivia Colman's splendid work in "The Favourite" was questionably submitted as a lead performance, leaving co-stars Rachel Weisz and Emma Stone in the supporting bracket.
Will win/should win: Mahershala Ali
Two years after "Moonlight," Ali should add a bookend for "Green Book," which, it's worth noting, easily could have placed him alongside co-star Viggo Mortensen in the lead actor race. It's a loaded category, but even with the complaints directed at the movie, hearing any other name would be an upset.
Will win/should win: Regina King
King already has a Golden Globe for her steely portrayal of the concerned mother in "If Beale Street Could Talk," standing out amid a strong ensemble. Amy Adams was just as terrific in "Vice," but in a role that didn't offer as many of the character beats that tend to impress Oscar voters.
Will win/should win: Alfonso Cuarón ("Roma")
The Mexican director's deeply personal film about the women who raised him was clearly a labor of love, which -- even with misgivings about its Netflix status -- should be enough to hold off Spike Lee's belated directing bid for "BlacKkKlansman." Cuarón should also prepare two speeches, given the likelihood he'll walk away with a second statuette, equally merited, for cinematography.
Will win/should win: "The Favourite."
The movie's satirical wit and juicy situations should carry the day for writers Deborah Davis and Tony McNamara, although frankly, the Writers Guild made a better choice with the indie movie "Eighth Grade," which didn't make the Oscar cut.
Will win: "BlacKkKlansman." Should win: "If Beale Street Could Talk."
The WGA clouded this race by honoring "Can You Ever Forgive Me?," but a win here feels like an appropriate consolation prize for Lee and his "BlacKkKlansman" collaborators, Charlie Wachtel, David Rabinowitz and Kevin Willmott. Still, Barry Jenkins' lyrical adaptation of James Baldwin's novel deftly mixed a sobering look at racial injustice with a touching, heartbreaking love story.
Will win/should win: Nicholas Britell ("If Beale Street Could Talk").
Britell's melancholy score should top a strong field of nominees, with "Black Panther" and "BlacKkKlansman" among the worthy alternatives.
Will win/should win: "Shallow" ("A Star is Born").
The Lady Gaga-Bradley Cooper duet is plenty deserving, but even if it wasn't, it's hard to believe Oscar voters would be shortsighted enough to pass up the opportunity to serve viewers another Gaga acceptance speech.
Will win/should win: "Spider-Man Into the Spider-Verse"
Disney actually released a pair of excellent sequels in "Incredibles 2" and "Ralph Breaks the Internet," but the dazzling animation of this Sony feature possessed a freshness that they inevitably lacked, and should complete its triumphant swing through awards season.
Will win: "RBG." Should win: "Free Solo."
This is a toss-up category, but the opportunity to laud a liberal superhero, Supreme Court Justice Ruth Bader Ginsburg, might be too much for the Academy to resist. That said, the climbing documentary "Free Solo" and its dizzying visuals feels more distinctive, although frankly, two omitted movies -- the Mr. Rogers doc "Won't You Be My Neighbor?" and separated-at-birth story "Three Identical Strangers" -- would have topped either of them. (Disclosure: Both "RBG" and "Three Identical Strangers" are from CNN Films.)
Will win: "Roma." Should win: "Cold War."
Yes, it's counter-intuitive to say "Roma" should win best picture but that Poland's entry should garner the foreign-language prize, but director Pawel Pawlikowski's version of a personal, haunting and gloriously black-and-white film deserves its moment in the spotlight too.
Will win: "Avengers: Infinity War." Should win: "Solo: A Star Wars Story."
The "Avengers" sequel was plenty impressive, but the quality of "Solo's" visual achievement -- and the variety of looks in its rich palette -- was somewhat lost amid the cool reception the movie received and its disappointing box-office results.
Will win: "The Favourite." Should win: "Black Panther."
Although the Academy usually loves an old-fashioned costume drama, the immersive look and feel of the Blank Panther's fictional kingdom of Wakanda is among the year's most remarkable accomplishments and a major part of the movie's success.
As for trends, if "Black Panther" begins piling up wins in technical categories early -- including production design, costume design and sound -- it could represent momentum toward a "Wakanda Forever!" kind of night.