The absolute KEY to having no moisture change induced issues with a wood stock is SEALING the pores of the wood. Many people simply assume that an off the shelf wood stock that comes on a rifle is properly sealed against weather. Usually, it ain't so. The INSIDE of the stock is the area most often neglected.
Anyway, with a PROPERLY sealed wood stock, there is never an issue with the wood drying out, cracking or swelling (due to moisture changes)....because the moisture content won't change. Some mistakenly believe that temperature is the actual factor at work - that a stock will swell on a hot day....and shrink on a cold one. ALL materials do change dimensionally with temp. change, but an amount so small as to not matter for this purpose. Change in MOISTURE CONTENT is the relevant factor. Prevent that from happening....and a wood stock will be just as stable as any other. Some also mistakenly believe that, once a piece of wood is kiln dried to a certain moisture content, that percentage won't change. That is absolute nonsense.
Again, IF the wood is not properly sealed, then the moisture content can and will change. Seal it properly....and the wood will be as stable as plastic.
A wood stock that has not been properly sealed....and allowed to dry out excessively, can be brought back via application of moisture, then re-drying to the optimum moisture content - if done slowly and carefully. However, ONLY if the "drying out" was not so excessive as to cause significant damage from shrinkage. If cracks have appeared, due to excessive drying - then things have gone too far. Such a stock is probably best used for firewood, at that point.
No question, wood stocks require more care than plastic ones. For me, though, it is worth it. For others, maybe not.