This simply isn't true. CPU mining is perfectly viable at 512 share difficulty. Share difficulty DOES NOT MATTER - it only increases variance.
It sounds to me like his stratum proxy is lagging - try pointing the miners direct to the pool and see what happens.
While my thing isn't CPU mining, a diff of 512 is giving me much higher rejects than a lower difficulty, which is obviously causing issues for me.
This is not true... you will see higher variance in rejects, and possibly spikes of higher rejects, but over time it evens out no matter what the share diff.
This is simply obvious - your chance to discover a block is proportional to your hashrate... shares are no different.
why not mine the top three profitable coins and split hash according to difficulty.. those tiny new coins are the money but for obvious reasons the whole pool cant hit it. diversify your coin portfolio.. have eu mine something and other pool something else... wemineall can mine several coins at once so a much bigger pool should easily dobit too
PoolWaffle has clearly stated he's working on it - this requires a massive re-work of the profitability switcher.