There is no other choice than Bret Hart for this 'season' - the closest was Shawn Michaels as he was the only one nearly as consistent.
Savage could have been but was hampered by the knee injury which cut his title reign short, and by the end of the year was predominantly used on commentary, as he was indeed at Wrestlemania IX.
Savage's title reign wasn't cut short by a knee injury. It was cut short because he requested to be taken off the road and ease his schedule post Elizabeth. There was an angle where Flair injured his knee at S-Slam to give him a face saving excuse in his subsequent title loss to Flair but the reason his own reign was cut short was because he wanted it to, he asked to be reduced.
HBK was pretty much a non entity till very late in 92 and was a mid carder at best even then. His initial push as a singles star started with a bang in late 91 and then stammered around very un-impressively till his out of nowhere IC Title win. Spending the summer wrestling jobbers and feuding with Rick Martel in a comedy feud over who the prettiest pretty boy was isn't a high light in his career. His IC Title win did move him up the ladder and he did get a World Title Match on PPV (S-Series) even if it played second fiddle promotion wise to star laden Tag Match (Flair/Hall vs Henning/Savage). He is not a legit contender.
U-Warrior was not used effectively early on, wasted on a mid card feud against a comedy act no one cared for or had heard of before (Papa Shango). It was clear going forward that WWE was banking on him at the end of the year, they milked the last dollars out of a rematch between him & Savage that they could get and then set up major feud with UW chasing Flair for the title, supposedly set to end with a Warrior win at S-Series. Warrior's continuing problems with other talent, his contract, and finally his causing Flair to be seriously injured and forced out of action pretty much doomed what should have been his return to the pinnacle of the company. After Flair was injured UW basically disappeared for WWE programming, returning briefly just to get punked by Flair & Hall on a SNME to explain his prolonged absence from WWE programming (and make Flair look strong in his return). Considering that he basically canned himself his own mega push and did little outside S-Slam 92 in the interim and had no value and barely any appearances after Mid Oct, he isn't a contender
Flair was an integral part of house show business and a major part of S-Slam 92's World Title Match. He wrestled in one of the most entertaining World Title Matches in WWE history and managed to win two Titles in one year, a rare feat, especially back then. Outside of an extremely long and drawn out feud with Savage however he didn't do much else with any other talent. He wrestled some entertaining matches vs Taker, helping to establish Taker's growing status as a fan fave. He was superb on the European Tour in title defenses vs Hart & Savage. He was the catalyst storyline wise that brought Curt Henning back inn active competition, and their RAW Loser Leaves Town Match in Jan 93 remains one of the most talked about RAW matches of all time. His planned feud with the Ultimate Warrior was cut short by injury. The injury wasn't his fault and he deserves major props for his willingness, despite the injury, to attempt and lose the title proper in the ring rather than just have the title be forfeited as he took a medical leave, definitely an old school take one for the team attitude. In the end I don't see him as the MVP during this period however, especially since he was done in early Feb 93.
Hart's IC Title win at WM VIII was impressive in a high profile match that was just a shade behind the double main event in terms of card importance and promotion. He was somewhat lost in the post Mania aftermath until his well promoted fued (and loss) against British Bulldog at S-Slam 92. Hart was seemingly out of the title picture when Warrior's self destruction necessitated someone step up and he, as a long time employee, loyal WWE lifer, popular fan fave, and hard worker was chosen. Sometimes being in the right place at the right time is the best way to be. As champ, Hart didn't hit his stride till after the new year, with too much attention on the returns of Flair and Henning and the continuing push of Hall, as well as the debut of Yokozuna. For awhile Hart was wasted on a meaningless run of matches against the ridiculous Papa Shango. By the beginning of 93 with a well promoted run of matches against both Flair & Hall Hart started taking center stage.
Savage's return to active competition and World Title Wins were the unquestioned high lights of 92. His performances at Mania & S-Slam and his hard work on the house show circuit were a major benefit to WWE. The fact he took himself out of the picture in late 92 and from then on never really got back in (how much of that was his fault and how much was Vince is conjecture but there are well documented stories and Vince not being happy when his champs ask for time off, just ask Ricky Steamboat circa 1987). Like Flair, if Savage had competed the entire time frame I would consider him better as legit contender. Since he was basically MIA from Sept on (save for token appearances at S-Series, R-Rumble, and Mania 9) it's hard for me to chose him over someone who was active the entire time.
So HBK isn't nearly important enough or contributed enough but he was active the entire time. Warrior was around for a brief period and left badly. Guys like Hall & Henning who I did not critique don't get mention since they entered the period so late and I feel even then others equaled or exceeded their contributions. Flair & Savage did quite a lot but still weren't active the entire time. Hart is the only one who can match Flair & Savage's contributions and was a major player almost the entire time, active the entire time. I also give him a bonus point for doing a good job keeping the WWE chin up after Savage begged off, Flair got hurt, and Warrrior was fired. It wasn't the ideal way to be given the ball but he ran with it none the less. Id give Hart my vote, a slight edge over Savage & Flair and clearly ahead of everyone else.