If I had to assume, I'd agree with you on the haptic feedback being stronger, bloot. But if it actually is stronger, its a very small difference. The motor doesn't feel any different than before, and I doubt a firmware update could make it stronger. But again, it does feel a little stronger.
As for the sound, tested it today and yes there's definite improvement over before. Still barely audible in some cases, but I'm comparing with my old iPhone 5, and honestly, the situations I'm comparing to are better suited for an actual speaker anyway, not some tinny phone speaker. So for most typical case usage, the speaker is pretty good now. Keep in mind the speaker isn't being touted as one of the phones features, much like a phone with stereo speakers, or higher quality ones. So with that in mind, the speaker on the nexus 5 is actually pretty good when you consider the price of the phone.
Sent from my Nexus 5 using XDA Premium 4 mobile app