Infantry rush!
I have a core of legionaries watching over the border with the Germans on the Alpine passes, to be supplemented with troops from nearby garrisons, of whatever mix I feel is suitable. Now I don't like fighting the Germans, who devastate my precious legionaries with their javelins, so I have some 4 slinger units available for any local battle. In addition to this, the Cisalpine settlements are churning out warbands for use as garrisons.
Out of the blue, a full German stack comes appears, with a core of jav infantry, but with absolutely oodles of slingers, archers, and whatnot. Enough to comfortably outmatch my slingers, and the battle will take place in the passes. So what to do? I decide on an infantry rush, with an all-infantry force, but for the general.
I see the battlefield, and I command a big slope, but the Germans have a little slope at the bottom, enough to give them some height advantage. They line up with what infantry they have in the middle, plus various mixes of missiles to give them a good field of fire. I line up, just out of range of their archers and slingers, heavy infantry in the middle, the faster moving warbands on the flanks. And once they had recovered sufficiently, I sent them forward, running all the way. Never mind subtlety, their goal was to run at the enemy, and continue running until they caught up with some, then hack away until the enemy flee, then run some more and kill some more. It was a fantastic sight to see this confused mess rushing all over the place. It reminded me of playing vanilla on arcade mode in my early days.