There need be no overall deleterious effect on the parent group, the post-evolution state better suits the members of the parent group because the troublemakers now have their own coin, which (some will maintain) is a shitcoin, bound to fail, can't possibly succeed, is already failing, etc.
Slimcoin is one of those Bitcoin's "sihtcoins" IMHO. And in its own group it does pretty well.
I do see a conundrum, though. The group health is inversely proportional with its size: in Slimcoin, for instance, at this very moment we can safely negotiate whatever we need to do, 'cause we're just a handful of people. Subsequently, the value of the coin is dimes. The only way for the value to grow is for the group itself to grow. At some point, the group health will start to suffer, precisely because of its size... Like Bitcoin "crushed" itself with BCC.
I wonder where the "goldilocks" area for such a group is - or if there is such a "goldilocks" area at all. How many people in the group: 100? 1,000,000? 10,000,000?