1. Single core processor: Honestly N9 doesn't need a dual / quad core to work smoothly. It provides better performance than some of the dual core counterparts
2. HW Keyboard: It is true that HWKb would have made it a great device. But, i hardly miss it. I have missed it only on a very occasions.
3. FMRx and FMTx hardware is present on the Soc. Its a question of writing an app to use them. It was a similar case on N900 wrt to FMRx.
5. HDMI: i miss it as well. But, somebody could use NFC to try and stream videos over Wifi (wishful thinking )
N9 is not the logical successor to N900. But, it offers you nearly the same kind of freedom like the N900. Its a better device with complete Qt integration.