How do we want to handle barbarians? I haven't come up with an exact 20-level progression, but I have several ideas I'd like to bounce around:
Temporary HP:
One sucky thing about rage is that you lose the HP you gain from your Con boost when your rage ends. To make these guys a bit more tanky, perhaps we could give them a number of temporary HP equal to their HD x 2. This would amount to the same number of HP, but these would be lost first, resulting in more HP for the barbarian at the end of the fight. We could also give a +2 bonus to Fort saves to make up for the fact that there's no actual Con increase.
Also, greater rage would become 3 x HD temp HP, and +3 fort.
Rage uses:
Instead of Rage 1/day at 1st level, how about 1/encounter? I'm not sure there's much point in giving multiple uses of rage per encounter, but perhaps each additional use granted from barbarian levels or some other source would improve the duration of rage by two rounds each. So an 8th level barbarian (normally 3/day rage) would have 1/encounter, but it would last 4 rounds longer than normal.
Pounce:
I'd like to just hand this out at 6th level. I'm not sure what to do with the lion totem from Complete Champion.
Shake it Off
Should we give the Shake it Off ability of the fighter in this thread to the barbarian? It certainly fits, but I don't want to make all melee classes the same in the end.
Alternately, maybe the barbarian can get rid of or lessen certain effects. Maybe something like getting a second save against exhaustion to make it fatigue. I haven't thought this part out much yet.
Improved Damage Reduction
The DR of barbarians is pretty crappy. I'd like to increase it. Maybe not all the time, but maybe when raging. Perhaps they add their Con mod to their DR when they rage.
Fast Healing
Perhaps barbarians should get Fast Healing when raging. I'm not sure how much. This might scale with level.
These are just my initial thoughts. I might come up with more later.