Yeah, the math on a Falchion with 1s and 2s becoming 3s isn't actually so bad.
A Falchion normally averages 5 per [W], because a 1d4 averages 2.5.
With that feat, the Falchion averages 6.5, because each individual d4 changes its distribution from 1, 2, 3, 4, to 3, 3, 3, 4, which averages 3.25...