The C&D really isn't that great for "permanent" invisibility because 1) you are easily seen through when it's at 0 power and 2) you can't move very far at all while cloaked. It's very good for avoiding being spy checked and sneaking past enemy lines but spy is so risk/reward that they don't need any more nerfs. Also Dead Ringer puts out the initial fire, but if you seriously keep firing for 10ms or so after you hit a DR spy, he'll still be burning while cloaked and easy to chase down. DR is just good for dealing with spy checks and that's about it, plus it completely gives you away when your cloak runs out unless you can retreat far enough that nobody hears you (good luck with that on all but the biggest of maps).