I have big feet, I'm 6'1"-6'2", with full size panniers on an axiom rack. As long as my panniers, Axiom Stormfronts and Arkel Bug are near the back of the rack, I have no issues with heel strike. There's not a lot of room left, but I also have the smallest frame, 56cm, that would fit me. The weight of the bike is insignificant in comparison to all of the gear that I load onto it. If you want to go lighter, there aren't a lot of options that still have the commuting accoutrements of the Crosscheck.