I cannot speak for everyone but I can tell you it is very annoying when the terms of a coin changes....ie another PoW phase.
Coin liquidity and total available comes into play when making purchase decisions and all of the sudden when things change and significant amount of coins are released/availability increased then you are diluting the holdings of the initial supporters who are here for the specs originally set forth. IMO best to stick with the original idea and figure out other ways to expose the coin.
What if 42 coin became 42k coin or 42 million coin....would that be good?
Situations change, and coins either adapt or die. The original concept behind the coin was Mastiff, if you recall, but that was decided to be changed by the community as well. A change in coin cap makes sense, following the rebranding to MastCoin, because the only reason for such a low coin count was to fit the Mastiff theme of value and rarity.
A second PoW period is also likely to be the best chance at growing the MastCoin community. However, if we all decide to move ahead with a second PoW phase, anyone is obviously welcome to sell if they don't agree. There will not be an "all of a sudden" change, it would be announced well in advance.