I've done quit a few beer can chickens and the first few where juicy, but the small amount of powdered spices added didn't really flavor the chicken much. However I decreased the amount of beer in the can to half a can (well I just drank half once because I noticed after the chicken was done I still had half a can of beer left that went to waste) and it helped quit a bit. I also added different spices that where stronger and seemed to work better. I recall doing a rosemary 5 spice with half of beer in the can and I really stuffed the can with a lot of fresh rosemary and used a few lime halfs instead of lemon that I just pulled off the plant on my patio and wow you could really taste the rosemary and lime. Instead of putting the space in the can I just rubbed it over the skin with a few other spices. The balance was perfect. I wouldn't bother putting any spices in the can with the beer, but stong things like rosemary, lime, habanero's almost always go in for a swim with the beer.