I happen to think I work with one of the pickiest vocalist I know here in town and that's my wife haha. She is not a huge fan of delays and reverbs and certainly not autotune. I sometimes have to twist her arm to let me put any reverb on her vocals....and believe me, she lets me know when it's not right
Anyway, on her record, we used the korby kat c800 capsule into a neve 1073 and did light compression using the retro sta level. It was a great combination for capturing the air in her voice.
As far as reverb went, it was mostly plate reverbs but we did tend to use more delays on the uptempo tunes. We did have to de-ess more than I hoped and looking back, I wish I would have caught some of the sibilance issues but lesson learned... I know some engineers that are very particular about how they de-ess and most end up doing it manually. Probably a better alternative.
As far as the "vocal space" found in a lot of the nashville records, I believe it comes from session players and producers that understand the vocal is the most important element of a song. Every part played and idea used should be to enhance the vocal and the lyric. Even with the pop influenced country sound in Nashville, I still think that underlying sentiment rings true. Anyway its late and I am rambling. Hope this sheds a little light.