you got it backwards. The faster the action the shorter the bend, the slower action the more of a parabolic bend (the majority of the rod will bend). Rods designed for crankbaits have what you're looking for...a softer tip. I throw a lot of different baits on my fiberglass crankbait rod..even texas rigged worms, But like Yudo said, the softer tip will make it harder to set hooks on baits like heavy jigs, T-Rig creature baits..etc where there is a lot of plastic the hook needs to penetrate through. I use it only for T-rigged worms and it works good.
I like rods with a moderate action than a fast action. But if Im using bottom baits where I need max sensitivity then Ill use something like medium heavy fast action