It's OK to wire stuff straight off the battery, as long as you put a properly sized fuse right after the battery. If you were running inverters or other heavy loads on the lighter, that would be a good mod to do. Also be sure to improve the ground wire.

I think Japanese cars are wired that way for safety, they don't want kids to be able to play with the lighter when the car is parked. Strange that American makers haven't been sued into submission over that.