what are your thought's on line diameter and sensitivity?  say you have the exact same setup(hopping a jig across the bottom), one with 12lb fluoro one with 20lb fluoro, do you think that the heaver line will transmit more "info" back to you, (rocks all that stuff you feel on the bottom) or the lighter line will. 

 

i was fishing today what i just described, but with 17lb and and it seemed to be more sensitive than my other rod with 12lb( same brand rod, line, and jig)

its just kind weird to think that different size is more or less sensitive

 

does anyone else notice this?

i would say yes because there is more line to transmit the vibration through and more importantly larger line stretches less if the same brand eg....stren 12 vs stren 17. stretch is directly linked to sensitivity, same reason braid is sensitive.

Maybe.  I can see why the thicker line would have less stretch and transmit more vibrations but I have never noticed this in any of my setups.  How deep are you fishing?  In deeper water say 10ft or more I'd say the smaller diameter line would be more sensitive as it has less drag to keep a bow in it and sinks quicker giving you a more direct path to the bait, even with fluorocarbon 12lb line will sink faster than 20lb.  Toss up depending on the situation.