hmm.. so I have to keep mining with Eligius in order to get back to expected return.
No, Extra Credit is included in the pool's considerations whether you keep mining or not.
I'm not particularly well versed in the mathematics of probability.. but isn't this a bit like the gambler's fallacy? ie just because I've tossed a run of 10 tails in a row doesn't mean I'm more likely to get a run of heads. Does the maths really say It'll come good for me?
Gambler's fallacy is the short-term; eg, just because you get 10 bad runs doesn't mean the 11th will be any better. For the long run,
the law of large numbers says the average reward obtained from a large number of rounds should be close to the expected value, and will tend to become closer as more we mine.
The problem with Ars was that it ran unmaintained for months and started mining only invalid blocks, then shut down completely. Why miners continued to use it after Burning Toad announced it was unmanned (heck, even now people still pop into the IRC channel saying they're having problems mining from time to time), I'm not really sure - but it does mean that so long as a pool is maintained, it should never completely die from impatient miners. That being said, some of
the SMPPS variants handle new miners better, and may be worth switching to so we can resume growth...