Surprised by the number of people still surprised that Siri doesn't search local libraries, given that it has been extensively discussed since before the release. A few people pointed out that it is not technically simple as the search is done in the cloud. But I think the reality is local libraries are much more of a niche audience and we all know that Apple doesn't focus on niche audiences. Lots of people on this forum talk about local libraries all day (and I have one too), but I don't know a single person that keeps a local library outside of these forums. The average person doesn't do it and it is not going to be a focus of Apples, and that shouldn't be too surprising.
I find the universal search to work quite well, it searches multiple services as advertised and it does prioritize free options over iTunes. The one thing I'm suspicious of is when doing a general search (e.g. a genre) I don't see many results for things that are not on iTunes, may be the search is driven from iTunes.
I do hope they update the interface for local libraries as that can't take much effort, but given Plex and other options are now available I'm not sure how critical that is.