Whichever you look at it, the police will always come off worse now, seeing how many people have lost faith in them, or their effectiveness. Arming all police isn't a great idea, i mean some could end up shooting themselves in the foot, and going on the stature of some, that wouldn't be far to go.
Corruption in the force cannot be done away with permanently as money talks, and no matter how good you are at your job, there could be an occasion when you end up stepping over that line, then its too late.
I would send the rioters to prison, on bread and water for a few months, don't see why they should get anything other than that. Unlikely that would happen as there are laws in place that prevent ill treatment of prisoners, look at Levi Bellfield who is suing, because he has been hurt whilst in prison.
The zero tolerance you spoke of, wasn't that the brainchild of one time Mayor Guillani, not sure, but there does seem to be something in that, as i read how many urban areas in NY, that were once considered no go, rife with gangs, drugs have been cleared out, and that is something that could or should be done here in London. Some of the gangs now have a number of areas in lock down, and you wouldn't venture there in the day, much less at night. This is not the city i grew up in, and no i don't like it much.