I've heard some say an ultra-light rod is more sensitive. I've heard others say the heaviest power rods are more sensitive. They're probably both correct, and I don't believe either one.
Sensitivity is the most over-hyped, over-marketed, over-propagandized term in this industry. and we've all drunk that koolaid to a certain extent. Being a completely subjective property; it is virtually meaningless.
For every person who claims "this" rod is most sensitive, there are some who will claim "that" rod is the one,, and some more who go for the "other" rod. Again, they're probably all correct, and I don't believe any of them.
I do believe that all other things being equal, a lighter rod is more sensitive. Starting with the same blank, build one to match a factory rod, and build the second with a lighter reel seat / handle assembly, and smaller, lighter and fewer guides(most rods have too many guides), and the second rod will out-perform the first. I believe that because I've done that.
And last, I think part of the differences of opinions on which is the most sensitive, other than fanboy adoration, is the way each person holds the rod while fishing. Which is in part a personal preference, to some extent dictated by the reel mounted at that time.
to the OP, these dyas, if you spend $100+ you're going to get a rod that will do the job nicely. Buy waht feels good to you, with the reel mounted. Then it's up to you to get the most out of it.
Sorry folks, I don't know what happened with that post. I had sectioned out in paragraphs, and it posted as one block. weird