It is obvious that plains are an unfinished biome, even more, when you compare them with Swamp for example. Now with the release of the new biome the Mistladns I wonder, are you gonna left the plains as they are? I mean, plains are just a boring desert, there is no thematic armor like the wood armor or Fenrir armor of swamp and mountain, there are no dungeons, etc.
One thing you can add as replacements for dungeons in plains could be a Gobling Fortress. Or something, I'll accept anything at this point. I just hope that this is not the final iteration of the plains we have because I really find them quite underwhelming.