The current karaf feature uses the wrap protocol in two places:
<bundle>wrap:mvn:org.rhq.helpers/rhq-pluginAnnotations/3.0.4</bundle>
<bundle>wrap:mvn:net.sf.ehcache/ehcache-core/2.4.3</bundle>

This should be avoided. wrap does not work well if people use hibernate as a boot feature and it does not work at all if people force signature checking of bundles.

For ehcache there is this bundle from servicemix bundles:
http://mvnrepository.com/artifact/org.apache.servicemix.bundles/org.apache.servicemix.bundles.ehcache/2.4.3_2

I am not sure about rhq-pluginAnnotations. It seems to be a redhat bundle. So maybe you can persuade the team that creates it to deliver a bundle out of the box?

For me the priority would be the ehcache bundle as it is easy to fix and many people use the validation support.