Should we make Merges easier to treat as Sources?

As mentioned by @QmQvl on gitter: is mergePreferred (http://doc.akka.io/docs/akka/current/scala/stream/stages-overview.html#mergepreferred) not available outside GraphDSL? having to write at least 4-5 lines of ceremonious code is not that much cleaner, arguably 🙃

There is some truth to that - as we know the GraphDSL is the "power user mode", yet already for a MergePreferred people need to drop down to it.

Should we re-consider and make all Merges be usable as "merge these things and give me a source"? I personally think it would be nicer this way, sending in a proposal PR.