Rerouting hot water to my shower

Background info, the sinks and tub in my master bath get hot water within a few seconds of turning on the water, but the shower literally takes a minute. The water heater is almost directly above this bathroom. Through investigation I have determined that the hot water to my shower taps off the line that feeds my kitchen sink. Therefore, the water has to travel about 30 feet vertically and 15 feet horizontally then about 20 feet back up before it gets to my shower. I have no idea why the plumbing was installed this way. I have full access to my attic and access to the top of the wall that this shower head is on. My plan is to tap off of a line that is in the attic route it around and then down the inside of the wall to my shower and cut the existing line and connect this one. My question is, since this will become a dead leg of pipe, should I also cut and cap this line in my crawl space where it is fed from to keep the water in the line from becoming stagnant and somehow getting back into my kitchen sink supply? Thanks for any input.

 

Good Idea to kill the line what good does it do to have the chance of bacteria , plus any line that's pressurized can leak . Zero gains vs potential problems vs a tiny bit of work

 

Thats the way I was thinking. Thanks for the input.