vortex said:
Sounds rough. Although I think the fault lies with the scenario rather than the system.
Agreed, but the variable quality of supposedly professional Cthulhu modules produced by Chaosium is a big indicator that competent modules can be difficult to write for Cthulhu and even harder to determine for a casual keeper. This applies double for long-term games - see Chaosium's own note about full-length campaigns under their writers guidelines.
I've found the opposite. As the base for say 'spot hidden' is 25%, its likely someone in a group of 4 investigators will make the roll. If you really analyse it, success is highly likely, the die roll is only to add tension and give the players the illusion of achievement.
Dice are fickle. I can think of twice in the last year where the campaign has ground to a halt because everyone in our group of five failed a roll - and this includes characters that have scores of 90% in some of the Cthulhu critical skills. On average, yes, things work out. I want the safety net of take 20, which ensures that if the dice go against the players they can still get the details they need. Tension can be generated by time constraints and interruptions to the search check, it cannot be regained once a blown die roll means the players have lost the clue forever.
Good scenarios should only allow randomness to give the player a slight edge. If the scerario grinds to a hold over a missed roll, there is something wrong with its design.
Again, I'll point to the variable quality of Chaosium modules here. Espeically once you get past the one-off session of attrition-based horrror. And for all its simplicity, my expreience with the BRP system has suggested that it can be downright horrible in the hands of someone who hasn't yet grasped the genre of Cthulhu. Simple systems are great for players, but often I've seen DM's flounder with the lack of guidance inherent in the rules.
Again, I have nothing against the BRP system - for short-term stuff where character development and gradual skill acquisition aren't essential to the plot it's a downright perfect game system. It's simple and easy to throw at people for a one off, and the rules perfectly capture the sense of impending doom coming up as the heroes grip on sanity is slowly stripped away. In a set-peice game where sanity and character attrition is expected I don't want a sense of character development or improvement - it's likely to thwart the feel I'm building. It's just not the feel I'm looking for in a continious campaign that runs for twelve months or longer.
Edit:
vortex said:
Leveling up is critical to character development in DnD. In fact, the desire to get more powerful characters drives the game. So what does the DM have to do? Beef up the oposition ro mach the PCs level.
I don't necessarily think the process of leveling up leads to considerable power-boosts in CoC d20. With the Massive Damage rules, hit points are essentially meaningless because even a 20th level character can die if bitten by a dog or shot with a handgun. The combat abilities, for the most part, are much slower.
What's important to me is that the players can add a +1 bonus to the characters skills at the end of every session or two - and they get to control where those points go. To be honest you could ditch the BRP Call advancement rules and offer me 10% worth of skill ranks that can be added wherever I want at the end of every second session and it'll address my complaint just as effectively. I could even live with a short-list of relevant skills that could be improved. I just don't like being at the mercy of the dice when determining how my character has developed as a result of his experiences.
My players are so into the feeling of unknown threats and investigating that I can spring an encounter whose EL is quite low, but which has them falling over themselves to flee. The EL doesn't matter, it's all about the description and the feeling of threat. 
Mostly in my games I go for a different magic feel than standard Dungeons & Dragons core rules and the magic rules in D20 CoC provide the help I need (with a little tweaking to remove sanity rules).
