you also not have to think these jumps in diff are only the known multipools.
There are guys already have ASIC´s for scrypt coins and have the power to do
switch their miners to the most profitable coins. These ASIC will destroy the
dezentralicised communitys and will let grow to centralised big investors that
can control the scrypt coins with their ASICS.

Small miners using GPUs will only pay for electricity and wont get enough coins to cover their
bills. You should also think about switching to some coins wich are ASIC resistant.