Did something new happend? Why are we seeing this kind of value crash?
Nothing is crashing, the value is going down, then it goes back up. Please, do some research on what a crash is, and then look at how [un]stable cryptocoins have been. People sell in mass quantities, which affect the value, people mine in mass quantities, etc..
I am pretty sure most miners realized alt coin pool profitability would be a flash in the pan as markets have a tendency to eliminate these types of conditions. Going forward i doubt alt coin pools will soundly beat just mining litecoin/dogecoin combo.