I've done a number of straight switch grass cover plots in the past, cave-in-rock variety. Field goldenrod has come up on its own and is not all bad because it stands well even under heavy wet snows.
I've also established some broad spectrum prairie that provides good cover. It has a lot of tall forbs which helps.
Next I think I'll be trying a mixture of the taller native grasses, big blue, Indian grass and switch. There are some quite tall native sunflowers that would be good in the mix. I think the advantage of a mix of grasses is that different ones thrive better under different season and location conditions so something should do well in each spot each year. Big blue seemed to really thrive this year.
I think about anything is better than brome and fescue neither of which is very wildlife friendly. A native grass and forb mix adds great color all summer and attracts a wide variety of wildlife besides deer.