Obviously, if some ppl do not get points on quick blocks, some other will do. This is, however, another unpleasant factor that you can hardly affect.
Umm... no offense bitdude, but if your hardware isn't submitting shares quickly enough in short rounds... maybe its your hardware. Up until recently I was only running GPUs and the VAST majority of short blocks were well within the acceptable variability one should expect in a short round. Short rounds are unpredictable. If your miner(s) happen to be working on a higher diff share(s) during the short round you may not submit those in time to get in the round. Its the nature of mining. If you've changed your diff on your workers, maybe consider lowering it.
All in all, the scoring system has some flaws that usually get fixed by Slush, but for the most part it works. If you don't like the variations in pay, thats ok, there are plenty of pools with very consistent pay (PPS or PPLNS). But don't go bashing Slush's system just cause you don't like it. Feel free to share concerns or ask questions, but bashing a system you don't seem to understand or like is kind of pointless.
None taken
Well my setup is as recommended - i.e. I have picked up the expected hash rate, which I did deliver in fact and the difficulty was selected. Hence if the difficulty setting is a problem here then the recommendation is poor in the combination with the scoring system. I'm not really saying that Slush's system is useless, it just does not handle these situations fairly - in my opinion. The scoring system itself should not, in my opinion again, force people to submit large number of low difficulty shares instead of working normal. I really think the suggested difficulty is correct here and it is the flaw of the scoring system. I think the problem is that it starts from the scratch with every new round.
I do not really want to offend anyone here, just explaining why I left this pool - i.e. it might be the case that more people did not leave just because of poor luck ...