There are several ways to make it better, keeping 1 thing as original production of wine... being produced x1.
a) Faster field growth: once built it can grow at half speed (actually preety fast), you use 12 timbers instead of 20.
b) Faster working rate: he recollects grapes, but then doesn't jump around 35 sec, but 15 sec instead.
c) Better condition: All the same as now, but gives an incredible +50% per unit (needs rebalance in many Maps storehouses).
d) Vineyard cheaper: Just -1 stone/-1 timber. Hit points: 250.
Perhaps slight combinations of these will give Vineyard the attention it should deserve.

A+B: Working faster means you would need more fields at normal growth rate, but no if A is active (fast re-growth).
A+C: Less wine fields required, and it gives x1 "fish" (50 condition).
C+D: This would actually be my favourite... but others are fine too.