My stroganoff comes out pretty bland too. When I'm not using Hamburger Helper powder, I use a recipe I got from my mom. It was originally called "Swedish Meatballs" but I'm too lazy to make meatballs 8-). I notice my Swedish Meatballs sauce uses beef bouillon where my Joy of Cooking claims stroganoff should use some white wine. So mine will be a little more salty, I guess. Otherwise the recipes are pretty much identical!

Sour cream is definitely a deadener. Maybe fiddle with it a bit, decreasing the sour cream? Maybe increase the onion a little? And I'd be awfully tempted, with this recipe, to toss in a touch of garlic or mix the onion with some shallots. But I am sooooo the wrong person to ask about experimentation. Most times my experiments turn out to be hideous. :-(