Why doesnt kat have a resource bar?

As an avid kat main, almost 200k mastery most played champion. I don't quite understand why she still doesn't have mana/energy like the rest of the mid lane assassin group. I was thinking she should be running on energy to give her more of a skill cap instead of just spamming everything like old kat did. I mean I don't really mind not having a resource bar with her, but it just seems to give her a huge advantage that she probably shouldn't abuse. (I.E Wow theyre oom just shunpo to them and kill them because they cant auto you to death)