Despite the win ratio for Allies, Plainscape and I played this one twice, with banner count for allies, 8-6 and 8-7. French felt like they had a chance in both games. Poor dice can do either side great harm in this one.
The fundamental problem with this scenario is that it allows the Coalition to act unhistorically: They have no incentive to be aggressive but, instead, can use their superior artillery to pound the French into submission.
The French right is key to their chances in this scenario. Here, the Grenzers make relatively easy pickings if the French player can bring their line infantry to bear. It is on the right where the French have best chance of launching a fruitful series of infantry attacks, with cavalry to support and the possibility of re-inforcement from the centre.
If the Allies manage to occupy a building hex, the French chances recede considerably with the loss of the 2 temp victory markers, as the Allies have so many more units to allow weak units to be replaced, whilst the French are worn down.