With the group lacking a real in your face front line fighter I'd suggest looking at the Titan Mauler archetype for the Barbarian.
We had a very successful Titan Mauler in our own RotRL game.
If the reach fighter is AOO and stand stilling everything that comes their way, however, adding additional crowd control might be a way to go?
I had a good time as a sorcerer in RotRL with spells like chains of light and river of wind and waves of ecstasy, etc.
A caster druid or a witch might also have utility in that area.
|Earl of the Malebolge|
Your party is lacking a skill-monkey style character, so might I suggest either a bard, investigator, slayer, or inquisitor? Inquisitor is my favorite of the three, but that might be my love of divine spellcasting.
I'm currently planning my RotRL campaign, and a skill-monkey would definitely be a good idea.
|Ulfen Death Squad|
Bards can be sick if built right. One of my friends has a bard for society play uses its song not to sing but for other cool things that hinder bad guys, like making them go in north-south and east-west straight lines. The same bard was able to charm a landshark creature into fighting for the group.