No, I don't think it is fair to say Luck has carried the Colts more. Andrew was drafted #1 overall by a perennial playoff team hat had Peyton Manning as the QB. Stafford was drafted #1 overall to guide a Lions team that went 0 - 16. He was 2-8 in games he started in his rookie year, and threw a lot of picks learning. But he also became the youngest QB to toss 5 TD passes in a game, doing so almost a full year younger than Dan Marino was when he threw 5.
The more I look, the more I see similarities, not differences. As far as seasons, if their 11 - 5 2014 season is what you refer too, I feel any team trying to get wins past 11 is very difficult... for P. Manning, T. Brady, D. Brees, A. Luck, etc.. Also, Megatron was hurt some that season. But the biggest issue Stafford might have had was the new philosophy of Joe Lombardi at OC. Stafford seems to gel much better under Jim Bob Cooter.. All of these things play into to it, So no, I cannot say A. Luck under J. Lombardi scheme at Detroit would have collected more than 11 wins in 2014.
I still give my QB the edge, maybe homerism. Maybe ceiling height, maybe intangibles... don't know, but to me they are close with A.Luck having an edge.