Hi, what Karaf version are you using?
I tested with Karaf 4.0.x and effectively the "-i" switch is not working anymore since KARAF-2888.
So you need to install the feature after adding the repo:
karaf@root()> feature:repo-add mvn:org.infinispan/infinispan-client-hotrod/8.2.0.Final/xml/features
Adding feature url mvn:org.infinispan/infinispan-client-hotrod/8.2.0.Final/xml/features
karaf@root()> feature:install infinispan-client-hotrod/8.2.0.Final
karaf@root()> bundle:list | grep "Hot Rod"
54 | Active | 80 | 8.2.0.Final | Infinispan Hot Rod Client