this. A thousand times this.

First, OP presumes hoarding is the cause of volatility and that the proposed solution is a clean fix for that, both of which are dubious assumptions. I'll counter that it is the buyers and sellers rushing in and out of poorly operated exchanges, not the hoarders that are causing volatility. Hoarders are generally waiting for the market to stabilize after long term price discovery has become much more efficient.

Volatility, in my opinion, will NOT subside until virtually everyone knows about Bitcoin and has made their decision about whether to participate or not.   Also, it probably needs to survive in some practical form after a government assault. We'll have waves of volatitily, probably for years, until that process is complete. Then we will have true price discovery. The measures OP describes cannot counter those factors; they are fundamental.

Also, it is totally unrealistic to suggest that the Bitcoin community would just collectively adopt these kind of changes. The entire Bitcoin community, by defintion, is voting for the current rules. If the rules are changed it would not be a magical transformation of Bitcoin into Bitcoin 2.0. It would be a fork, and I will stick with the block chain using the original rules and will not participate in the new coin. If they had value I'd sell those Radioactive Bitcoins immediately and buy more Original Bitcoins.