I'm not a weight watcher myself, I even have an old school pattern plane, Class C, that was designed to be as heavy as it could be. The designers thinking was he traveled all over the country to compete and in all weather conditions, wind for the most part. Keeping in mind this is a pattern plane, not a 3-D plane. In 1966 3-D was still something seen in a theater.
That being said I still try to keep the weight down during a build, I don't feel that adding weight is a good thing either. On my last build I had no other way to get the proper CG and had to make a formed lead weight and installed it as a nose ring.
6 ounces in a sport plane is no big deal but I still try to CG by moving the gear. A battery pack in the nose like John Buckner shows quite often is just one great way to do it. A heavy spinner or weighted prop nut works pretty well too. Not a first choice but I like them better then just lead weight.
I live and fly in an area where high wind can often just be a normal day. The ultra light planes get bounced around quite a bit. When the wind comes up I just pull out my old daddy Rabbit pattern plane. It's heavy for it's size and it too gets moved around a bit in the high wind but it was designed for it. It's much better then it's light weight cousins when it starts gusting.
The idea of Ultra Light planes came about when ARFs started taking over. They don't have much wood in them compared to a kit built plane so they had to say something. People bought into the Ultra Light thinking and now preach it to others. Myself, I would rather have a bit more weight and a stronger plane. I also can't fly 3-D so it makes very little difference.