Two final points and I am outta here for a while...
1. The pruning in Bitcoin is technically doable (and Satoshi very vaguely mentioned it in the seminal whitepaper), not likely as efficient as the MBC, but I wonder if the pools will even allow it to happen. They may have an incentive to make it more difficult to run a full client. We debated upthread whether users can solely dictate hard forks, or whether mining inertia is also in control of that decision. (so I won't rehash that discussion)
2. There are so many of you out there who don't have enough income and have more free time, I don't understand why many of you wouldn't be spending $200 per day on a 10,000 computer botnet and mining these CPU coins in order to generate more capital to invest in Bitcoin or which ever coin you think is the best investment. The link I shared upthread says the mining GUIs are "point and click" in the botnets, so probably even a dummy could do it. Assuming it is profitable, the only issue is legality and morality. I personally think it is immoral to not expose a natural weakness (both in the crypto-coin and on users' computers), because nature requires we do in order to maximize resilience and prosperity overall. Note I didn't comment on the legality. For example, maybe more users would move away from that spyware Windows 8 and to Linux if more users are seeing their computers slow down:
http://en.wikipedia.org/wiki/Usage_share_of_operating_systems#Desktop_and_laptop_computersEven though other nefarious uses of a botnet can potentially generate more profit, mining is just so much easier and (at least not factoring the theft of other users' computation, the mining aspect is, versus say stealing credit cards with the botnet) less criminal.
Thus I see these CPU coins with near-term high debasement rates and no botnet resistance as sitting ducks waiting for their price to be in a downward spiral. Some whale could end up with too many coins by sitting on the bid (as the botnet miners dump coins), and end up killing the network effects and thus his investment. Look Ma, I own all the currency. Ma replies, "Aren't you a little bit lonesome?".
Edit: the criminal liability is more than anyone with reasonably good opportunity cost would stomach, but for those who have less alternative opportunities and or who under financial distress (or those with a criminal mindset who don't calculate probabilities well), they would be probably wisest to botnet mine an anonymous coin where they have better chance of concealing their coins.