There are so many standard capacity magazines out there now that a ban would be utterly pointless. You wouldn't be doing anything other than limiting concealed carriers to 10 rounds and letting criminals have however many they want, because dumb laws like this do not solve anything, they just give the government more power, which they either abuse of prove their incompetence with. Your law would handicap those who would not use a magazine to shoot innocent civilians. Also, high capacity is disingenuous. The standard for the M16 was 20 rounds and now is 30 rounds. The standard for a G17 is 17 rounds. IIRC, NYS has never used the magazine ban as an outstanding charge. It is always used in cases where the DA is trying to throw the book at someone. In my area, the police don't really care, some of them even have post-ban mags for their guns.
Explain this to me, why should the police have "high capacity" magazines, when they have backup, bullet proof vests, and no legal obligation to stay and fight?
As for "no private sales", that didn't stop Jared Laughner, who bought his gun from a licensed dealer (if you will recall, his magazine malfunctioned, probably due to it's capacity vs. what the gun is designed for, it's size allowed for a grandmother to grab it, and h was almost shot by an concealed carrier)
It won't have an impact on violent crime, because 90% of violent crime involves no firearm, 94.4% of gun murders are gang related, who get most of their guns from theft, and even when a gun is present, it is not used or threatened to be used 83% of the time
70% of the time, criminals get their guns from off the street sales. However, 71% of the times, those guns were stolen.
It didn't stop the columbine shooters, they used a strawman purchase (Who, by the way, used low capacity magazines and an illegal handgun). In the age where one could buy a Tommy gun with a silencer, Drum mag, and all the other goodies at a hardware store, there were no school shootings.
What you want is control, because you don't trust people. You do, however, trust the government, which is a far bigger threat to your freedom than your average American, gun owner, or hunter. Just remember, it's a bill of rights, not a bill of needs
ETA: On the subject of waiting periods, after the one under the brady bill came into effect, Murder and robbery remained at the pre-bill levels, and rape+ aggravated assault began an increase. The difference in homicide rates between states with the waiting period and without it are negligible. The average gun used in a crime is usually stolen, and goes an average 1-12 years after purchase before a crime is committed.
Suppressors are barely regulated in some countries, and they have no issue with assassin style killings. It should be a matter of courtesy, the only guns that become Hollywood quiet have terrible ballistics. I would love a suppressor, I hate wearing ear protection, I can't hear the game I'm stalking with ear plugs in, and when I'm hunting dangerous things like boar, I prefer to hear everything that's going on. Plus they are useful for not losing hearing in self defense situations.
None of your solutions would come even close to saving a single life.