correction he can effectevely sensed people without kcmMinato needs to put his finger on the ground in order to effectively sense people (without KCM). Sasuke, juugu & suigetsu all sensed naruto's chakra as well..
if not the greatest sensor, at least he has the basic... its because he needs it to identify opponents position after FTG... for example.. when he landed after FTG, his opponent may at his blind spot...so to react to that faster,he need to sense chakra... it requires a bit more time to scan around with his eyes to identify enemy position, every seconds to minato means life or dead...Yes, he is one of the greatest sensors in Narutoverse, his sensory is advanced than most sensors. And that is one of his feats that make him a wonderful user of his FTG. He can sense exactly where the enemy is, whether an enemy is approaching him and a lot more.
What? No, sasuke & co. sensed naruto & kurama as well.correction he can effectevely sensed people without kcm
since the chakra he sensed was without kcm he sensed both naruto and kurama cooperating
while the sensores only felt the fierce chakra of kurama