One thing to remember about the power level is that it is not an absolute scale, but each individual player trying to find the right mix between specialization and generalization - more specifically, balancing being good at their main role and being able to function outside of that role without any glaring weaknesses. The space on this continuum will vary by character concept.
A street samurai might want combat skill dice in the high teens, since combat skills are an opposed test with lots of potential negative modifiers. But you can overspecialize even for a combat character. A character with a dice pool in the 20's who can do nothing else is stuck in a rut. Despite his skill, he will be little more than dumb muscle, sitting there bored while the other characters do legwork, interact with contacts, and infiltrate places where you can't go in guns blazing. If the character has a slightly lower dice pool for combat, but can can spot an ambush, sneak up on someone, drive a getaway vehicle, interrogate someone, patch up a wounded teammate, and so on, then that character will probably get better, higher-paying jobs than the first character, even if he throws a few dice less for pistols. So even for a more specialist build, you can be too specialized.
On the other hand, a lot of support skills don't need to be so high, since they don't suffer as many negative modifiers, and you often get an extended test to do them (and can do them during downtime, rather than when the pressure is on). And some skills can't be as high, because not every skill has the same number of possible dice pool modifiers. If someone is playing a private detective, they might have more average Attributes, a high perception, some data search, some stealth, some social abiity, and enough combat ability to fight off a security guard or too. He isn't a powerhouse like the street samurai, but has more versatility. Generalists, though, have to be careful not to spread themselves too thin. If you do a lot of different things, try to do them moderately well. Don't be nearly useless at everything; even generalists need some focus.