Looking at it from a cost perspective, Jack of all Trades is pretty amazing. That +10 to everything is much like investing 20DP in every skill. You don't get that kind of skill mileage from Essential Abilities.
Would I be right in assuming that you think skill-based characters are underpowered, but still worth playing for utility's sake then?
Skill-based characters don't have the same oomph as other characters, no, not in combat
. A completely tricked out Assassin, designed for combat, is going to flat-out lose against an equally tricked out and designed Technician, Warrior, etc.
Of course, the smart Assassin isn't going to go head to head with these guys. But that's besides the point.
Given the kinds of games I run/play, a skill-based character is going to do just as well overall in the game as a combat monster (possibly better). Combat is infrequent, social interaction occurs fairly often, I don't ask for rolls for everything but I DO look at the person's skills for an idea of how things might go, etc.
So there's a lot of value in playing a skill-based character in my games. Combat capacity alone does not make for a fun time. :) The group's combat monster, a Warrior Psychic, is fretting about going to Gabriel (where they're heading right now) based on the idea that no, she can't dance. And going to a party is going to be a little embarassing if she can't do that.
Last level, she dumped Free +10's in both that and Style, commenting 'they still stink, but it's a start'. And constantly bugs the Windrider to give her dance lessons and the Assassin to tell her about the history of the place, to try to school her on the particulars of the nobility, etc.
Now, being a fish out of water can also be fun. Which applies both ways - the combat monster trapped in social circumstances, and the skill-based character caught up in a seriously dramatic fight...I'm currently playing a deliberately-unbalanced character in an online game, an Orochi-blooded, mentally damaged, horribly Cursed Technician who is completely out of her depth in anything but straight-up combat. Given that after a couple of thousand posts, we're into our SECOND fight, we're not getting a lot of that...but 80% of my fun playing the character is watching her struggle to muddle through circumstances (and failing miserably, having to get the rest of the amused group to bail her out).
Short answer :). Yes. They aren't as combat capable, but they're still very
useful in a game that doesn't focus exclusively on combat. And a ball to play, based on my group's Assassin's enjoyment. ^_^
Milage, of course, may vary! :D