If a player picks a subclass do they get the subclass abilities in addition to the regular class abilities? I suspect this is the case. For example, the Berserker subclass mentions that weapon mastery stacks with the Berserker rage increase in attacks per round, which can result in a staggering 5/2 attacks per round, even though weapon mastery is not listed as a Berserker-specific power ability. 

I ask mostly because this seems to make the subclasses super-powerful. I'm preparing to run my first campaign in this system and I'm trying to predict imbalances within the party. If everyone makes standard class characters but one PC rolls well then that PC is, fairly, at an advantage over the rest of the party. But, then subclasses have attribute requirements, typically higher numbers than average. This means subclasses grant even greater powers to characters who already have an advantage. I know not all subclasses require very high numbers, but overall they favor characters who already have better stats, and then give them cooler abilities.

Also, if PCs get both class and subclass abilities, then I'm confused about saving throws. Do the bonuses stack between class and subclass? Or do subclass saving throws supplant class saving throws?

Without having played yet, it makes more sense to me that the subclass completely supplants the basic class in all ways, though that doesn't seem to be the case. Thoughts?

Thanks!