I don't understand your claim that they are "encouraged to power attack and not crit because he'll probably dole out less damage than the rogue". The Slayer's bonus damage is a flat bonus and thus multiplied on a critical hit. Furthermore, level 17 does not immediately change the play style; that's assuming that every creature you fight will have immunity to critical hits and critical hits were something to ignore before level 17 because they never happened.
Out of combat abilities? I did mention that this was using the 4e Fighter as a base, right?
Jokes aside, out of combat abilities can be added later if needed. The core of the Fighter class should be whether it is functions well in a fight.