I agree venison does not always require to be masked for excellent table fare. That being said I have had animals that required a bit of tenderizing for whatever reason or just a change in flavor. Buttermilk, Yogart, Beer, Wine, etc will all work as a merinade. Anytime you want to tenderize you need an acid, but not over powering, so you'll want to offset that acid with sugar, spice, etc. Another way to tenderize is minute steaks, I run minutes steaks every year of game, I simply run in one direction and 1/4 turn them through again. Any butcher shop or processor should be able to this for you for a small fee, however the ways to prepare minutes steaks is subject to the fry pan (so IMO limiting but a nice change of pace!!)

A Fan Favorite for Grilling of mine is as follows:

Venison Merinade

Cut meat into medallions or cubes (smaller the piece the less duration required in merinade. Not to small due to grilling)

1 Cup Olive Oil
6-8 Cloves of Chopped Fresh Garlic (can very depending on tastes)
1 TSP of the following:
Oregano, Seasoning Salt, Lemon Pepper, Garlic Pepper or Black, Thyme, Rosemary, Dried Chives, Parsley and Maggi's Oriental Seasoning(if desired.)
1/2 TSP Marjoram & Paprika
2 TBSP Soya Sauce
3 TBSP Lemon Juice (Fresh squeezed is my preference not bottled)
3 TBSP Pancake Syrup (Canadian Maple of course)

Put in stainless steel mixing bowl, pour merinade over top and mix. I like garlic so I sprinkle garlic powder overtop of the meat once mixed(not required if you don't favor GP). Cover and refridgerate. I will mix it every 4-6 hours up to 24 hours to ensure all pieces are coated.