My K5 seems sharp enough!
I am inclined to agree with you. When B&H had K-5IIs for $699 I bought one and returned it. Fine DSLR but I could not see hardly any difference on tripod shots using the same lens (FA 31mm) and settings on both the K-5 and the K-5iis. Took over 50 images under the above conditions.
May try a K-3 later in the year,