I can commiserate. I think I fucked up a brayer too. OK, so here's the print done on plain old printer paper. I don't think the cards I use look awful but yeah, they don't look the way I want them to look. The end goal for the project is a gift for a family member which means you may be right. At least you're on to something about high expectations. 
I thought the pics you posted before looked great but I do see the difference between those prints and the detail here so there's definitely a difference happening with that paper that is detracting from your design. I don't know enough (read anything) about printmaking to give any advice but it looks like smoother paper is better? That stated, I freaking love this design!
Thanks! I do feel the other cards are usable and I'll send them to people myself, for sure. The plan is to make 4 bird stamps of local birds to make a stationery set for my mom. This is a red-wing blackbird (I'll color the wing on the final!) and then I think a bluebird, woodpecker, and a heron. I've had this plan for a while but been intimidated. This guy went well and I feel good about the rest of the project. I also have a couple of months thankfully. The trick is, not to let initial success lead me into overconfidence with the bluebirds. :) I guess it's kind of my new longer term craft project so, I will remember to post as I finish them.