So it does work for you for a short period...
Care to elaborate?
You move hashingpower from pools with bad luck to pools with (hopefully) more luck, by hopping.
This will increase the total of blocks found in an hour = increase of difficulty.
Hopping doesnt increase the likelihood of finding a block, it only moves the the same hashing power to a new pool hoping to get paid more per share due to proportional payouts.
There is no network hashrate increase/more blocks found(out of the norm) or anything, simply poolhopping cant rewrite the luckfactor involved in finding a block, that is random and allways constant.
If you dont understand the concept then please dont comment on the effects it may have.