why do you want the source to be open?
Because right now slush and his server are each a single point of failure. If either one becomes unavailable we have to go back to mining individually. OTOH if the source is available any one of us can take over in that event.
it would just enable others to create new (and eventually cheating) pools, which is one of slush's reasons not to do it.
I'm not too worried about that. I expect that over time we will be able to tell whether or not a pool operator is cheating.
Oh, and about this:
Mtgox and MyBitcoin are close source. I think shutting down those sites will have much larger impact on bitcoin network and nobody is asking for opensource it.
I'm not asking for them to be open sourced because I don't use them. All the bitcoin software I do use is open source, except this one.
