4. Clutch factor and Playoff performance
Winning at the end of the day is what matters in the NFL, and while the greatest prize was not obtained by Luck, he was still a very successful Playoff quarterback and performer. He took this team to two Divisional Rounds, an AFC Championship, and one WIld-Card loss back in his rookie season. Having iconic performances also helps out one's case in getting to Canton, which Luck has.
That aforementioned comeback against the Chiefs is one for the ages, and it is one that still gets talked about almost a decade later. Luck was known as one of the most clutch quarterbacks in the league with 21 fourth-quarter game-winning drives, 17 of those being fourth-quarter comebacks.
Being a quarterback that you know teams would pick if they needed someone to make a drive with the game on the line really helps out your legacy and how you are talked about, and for the Hall of Fame committee, this has to be part of the discussion.
If Luck's career continued, he would have had many more of these comebacks and drives, and yes, all we have to work with is what he did when he was on the field, but it is tough not to think about even if you are selecting who should be enshrined.