Hi Jae,
Three of us have now received dismissive rejections by those in control of Go. The three do not include myself. I don't know Go well enough to become another strong voice. However, even if I gained the needed Go expertise, I have no reason to expect not to get a fourth dismissive rejection.
Even if your ultimate goal is to see Go changed so that Gocap is a supported ocap subset of Go, I see no downside to first forking the language. If your language is both better, and Go-like enough to port many old Go programs and programmers, then it can become its own success. The existence of such a fork, or even its prospect, brings a new kind of pressure to bear, which is complementary to the pressures applied by arguments and advocacy.
Long live Gocap! I wish you luck.