The three day limit for unprocessed background checks is not a loophole. It's protecting a citizen who is not prohibited from possessing a firearm against an indefinite period wherein his or her rights have been infringed without due process. A reasonable compromise would be to lengthen the period but to keep it limited.
As far as women being shot and killed by their domestic partners, perhaps they would be better off by arming themselves with a firearm and training in its use than by a restraining order.
Child access prevention laws are good but they're reactive. They only come into play after there's been a shooting. Enforcement of such a law would require gun owners to submit to government inspections of their firearms storage. There very well may be some Fourth Amendment issues. And having to lock up all firearms when children are present makes a home a more difficult to defend gun free zone. The more sensible alternative is to keep firearms under control of a competent adult.