Some further edits made to the compendium post. The path mastery bonuses have been changed, as has the math for calculating mastery level.
Those have been the hardest part of the design. I want to encourage specialization, not merely to hand out small bonuses at random. So I've set the Path Mastery to "number of powers from that path, minus 1." The minus one part ensures that taking just one power from a path, or taking a feat that boosts that path, won't give you a "mastery" bonus. You have to invest at least 2 powers, or a power and a feat.
I may change it so that its "number of powers from that path, but a mastery level of 1 has no effect." That way you always start out with at least a bonus of 2, but you don't get anything from being a dilettante.
Those have been the hardest part of the design. I want to encourage specialization, not merely to hand out small bonuses at random. So I've set the Path Mastery to "number of powers from that path, minus 1." The minus one part ensures that taking just one power from a path, or taking a feat that boosts that path, won't give you a "mastery" bonus. You have to invest at least 2 powers, or a power and a feat.
I may change it so that its "number of powers from that path, but a mastery level of 1 has no effect." That way you always start out with at least a bonus of 2, but you don't get anything from being a dilettante.