Yes, Apple drastically needs transcription. That's why most all techies use Google Voice for voicemail transcriptions. However it's taken Google many many years to even get as good transcriptions as they are now which still is far from perfect. So I don't expect Apple to start off very well unless they buy up some companies. On the bright side they could get better fast if it's enabled by default for all their millions of customers.
The siri part doesn't sound too exciting. Ultimately rather than a voicemail saying, leave your name and number, etc. Sounds like Siri would say it and allow it to be a little more interactive such as, "What is your name?" What is your number? (even though both of those are typically captured in caller id), and what is your message etc. Think it may be more annoying to end users than not for a long time.
The siri part doesn't sound too exciting. Ultimately rather than a voicemail saying, leave your name and number, etc. Sounds like Siri would say it and allow it to be a little more interactive such as, "What is your name?" What is your number? (even though both of those are typically captured in caller id), and what is your message etc. Think it may be more annoying to end users than not for a long time.