Whisky instead of wine in marinades?

The main factors a base liquid can contribute to a marinade are:

• Bulk -- enough volume to reach all of the food.
• Acidity -- helps tenderize the surface of meats, and provides a bright flavor balance
• Sweetness -- helps provide a flavor balance
• Viscosity -- helps the marinade stick to or coat the target food
• Enzymatic activity -- some liquids (such as pineapple juice) have active enzymes which can break down proteins, tenderizing them in the short term (with the danger of turning them mushy in the long term)
• Flavor profile -- contribute flavor to the marinade, and thus to the food it adheres to or sauces it is eventually incorporated into

You did not provide a recipe, but in most Chinese dishes, the vinegar or rice wine in the marinade contributes some acidity (rice vinegar not always being as strong as western vinegar), possibly some sweetness, and of course, the characteristic flavor. However, Chinese marinades are not normally used for long enough periods, nor are they acidic enough for the acid to be an active ingredient; it is just part of the overall flavor balance.

Therefore, whiskey should serve well for most purposes, assuming you like the flavor it brings. While it probably has less acid than vinegar or wine, this is unlikely to be a significant difference.

There's no downs if you are using it as a flavoring and it adds the effect you are looking for, except maybe cost. Good whisky is very expensive compared to wine or vinegar.

Wine and vinegar are acidic, and acids can be used for tenderizing meats as well as adding flavor. Whisky is only mildly acidic, so it's not a good choice if you want to tenderize, if there's a downside it's that.