If they're installed on the same cluster you could still limit it to one keystone per node => no `keystone.conf` conflict.  Also, one obvious use case for multiple keystones is deploying multiple clouds from a single Crowbar (e.g. test, dev, production).  That was always a target of Crowbar (even more so since 2.0, hence the choice of the word "deployment" to replace "proposal"), and I think we should definitely allow for that in the future since it's obviously useful and low-hanging fruit.

But all that aside, the only real benefit of changing cluster resource names to reference OpenStack services rather than roles is a marginally prettier Hawk / crm output, and I think we have more important things to worry about right now.