As a comparison, here are all the courses I've played I put as 5s...
Saddle Creek - CA
Murphy Creek - CO
Palouse Ridge - WA
Circling Raven - WA
Jack Nicklaus - Promontory - UT
South Mountain - UT
Thanksgiving Point - UT
Stevinson Ranch - UT
That's a pretty short list of 8 as I've played 123 courses total now. Another way to look at it is, my top 26 courses played are 5 or better on the DS. The other 97 are 4 or less obviosuly...which works out to about only 1 in 5 courses I've played I put at 5 or better. So I don't think that ratio is out of balance.
Many on here might be familiar with Stevinson Ranch in CA, so that may be a useful reference point. As another measuring stick, I rate Tumble Creek as a 6, Black Mesa a 7-7.5, and Chambers a 8.