My main request is that if you do decide to support ISO, you also consider including the option to swap the split right shift with the 1U Function key to its right (so the 1U is on the left and the 1.75U right shift is at the very right of the keyboard). This minor change, in combination with the ISO Enter key, will allow you to support JIS as well as ISO.
It's only useful if you decide to support ISO though, so if you decide to keep things ANSI-only you can ignore this request :-)