Ok...after 7 straight losses I started digging into the details and figured some stuff out. Custom battle (10,000 denarii scale) my force:
(The Losers)
1 gen
2 leg cav
2 cav aux
all variations of infantry combos...glads, arcani, cohorts, triarii, hastati, principes etc...some w/eagles
variations of scorpion, onager combos
velites
archers
(The Winners)
3 gen
2 praetorian leg cav
1 leg cohort w/eagle
2 leg cohorts
2 triarii
2 aux archers
1 onager
1 peasant

I usually just let the computer pick the germans. Off hand from memory it usually kicks out:
2-3 gen
1-2 noble cav (this varies with how many gens but usually 3-4 cav type on the field)
spearman utilizing phalanx in the center
axe man
swordsman?
berzerkers
and at least 3 of those god awful screaming "ladies"
skirmishers of some sort
This stuff must be cheap because the computer is often able to field an equal or BIGGER force and even add a chevron to one or two units

I looked at the numbers, germans VERY strong attack, but not necessarily strong defense. The setting, Germania forrest scene (custom battle) with both units in offensive mode.
I have often used my roman formations in depth and on defensive posture with counter attack punch depending on cav action on the wings. This has worked in Thrace, and Gaul. It does NOT work with germans.
The battle that won:
left rear deploy area-
left wing gen w/hvy cav
legions in the center
triarii on each inf flank
gen behind leg
onager same

peasants out in front in middle of field...sucks to be poor and bait
aux archers behind but close enough to run behind legion inf

gen w/hvy cav and aux archers in right front deploy...immediately circle through woods to avoid detection and behind german line advancing

bulk of german cav circles to my right flank but stays put while german lines advance
peasants run to my left
archers pelt advancing inf, onager same
german right wing inf moves on peasants
my left wing cav moves into attack and melee
german right wing balks then sends support from center
german cav launches into my right wing inf, I pull left wing triarii into support of right wing triarii and legion inf. Counter with my gen when charge stalls
I attack with hidden cav from woods to german rear creating real chaos and pelt with my archers from the woods too
Now that I have german spearman going in different directions I commit everything into the pot.
Bloody day, lose half my troops in the end but wipe germans from the field

Conclusion...Germans VERY tough, have to hit them really hard and they will break, keep them running, they re-form well.
I don't think this stategy is that great, there has to be a better way. Lose way too many men. On replay I noticed something....Friendly Fire is insane. Lost many men to it. I understand its very common thing, but I think this is on a little drastic scale. Anyways, this is long winded and segmented. Thanks for the replies