Why would going from wood to plastic improve accuracy?
Composites will do better in foul weather (especially if barrel is free floated) in what regard? Only possible difference I can see is if the wood is not properly finished, inside and out, the wood may suffer some minor moisture damage that plastic wouldn't. But if the wood forearm is mounted with a single screw hanger bar, even if it was soaked enough to swell or warp some it would not change the barrel being floated or its accuracy.
The proper fit of any stock to the shooter reduces felt recoil, no matter what it is made from. The generic one size fits all factory wood stocks (and grips) can easily be improved on with a stock made to fit a shooter properly, either a custom stock or modified factory stock. It's harder to make a generic plastic stock fit you. Proper fit of the stock (or grips) also improves consistency, and so accuracy.
Choosing one over the other is just a personal preference thing more than a functional thing more likely.
I personally see no benefit switching from wood to plastic, and in fact just the opposite. My preference is wood, for fit and feel, for the weight, for the looks and because it is quieter in the field than plastic.
IMO-YMMV
