I wouldn’t expect major improvements in the traditional “non-A.I.” Siri.
For example, I have an iPhone 13 mini, which doesn’t support Apple Intelligence. I don’t notice any particular difference in Siri behavior on iOS 27 when compared with iOS 18 or 26. To be fair, I only use Siri for basic searching, so I am not exactly pushing hard on it.
No, there won’t be any difference in how Siri responds on a HomePod at this point. We use Siri heavily to control lights in the house and haven’t noticed any changes.
I just read that I will need new HomePod Mini’s to experience the upgraded Siri.
I have recently been experiencing very bad responses from Siri with news requests (especially for NPR or Headline News, not so much Apple News) on my 2 HomePod mini.
This caught my eye because I was just about to order a HomePod Mini to replace an old Alexa unit I got at Christmas party a few years ago. Will Siri on the currently offered HomePod Mini behave like old Siri, or will it be more like Siri AI on my iOS 27 iPhone? @ace and @josehill seem to be saying it will be more of the former. (Still, probably better than Alexa.)
You definitely want to wait—the current HomePod mini will not be able to support Siri AI as far as I am aware. It simply doesn’t have the processing power.