I am with you all as well! I love and use Siri regular as well as Google voice search via Chrome on my Desktop in Windows 8.1.1 - and I also agree the inherent speech recognition is older technology and I do not find it nearly as effective as the other two.
I would LOVE to get Cortana on my Desktop version of windows. It would instantly remove my need for Chrome on my Desktop and enhance user experience in most all input aspects of Windows 8.1.1
I am now accustomed to using speech recognition 90% of the time on my mobile for entering messages, emails, asking questions, setting appointments, setting timers, making calls, running applications, etc.
Adding to Windows 8.x would be the smart move in my opinion and get people to flock to Windows 8.x
Ed Parry
Computer Geek since 1981