1. IMHO, low volume (and the complexity, support, and returns). HA just isn't mainstream yet. Would be interesting to what he says about this.
2. My Leviton wall switches support instant status updates. Look for the feature "Supports Instant Status".
http://store.homeseer.com/store/HomeSeer-Z-Wave-Dimming-Wall-Switch-Matrix-W16C64.aspxhttp://store.homeseer.com/store/HomeSeer-Z-Wave-OnOff-Wall-Switch-Comparison-W7.aspx3. It is odd that temp is pulled (aka polled) rather than pushed instantly (like motion tripped/untriped). My guess is it's battery life. To listen for the controller to poll you vs transmitting until the controller responds probably saves some juice.
Interesting note, the 'Poll this node at most once every' setting are irrelevant if the device is sleeping, it's skipped when it's turn. It's the 'wakeup interval' that updates the temp/humidity/light, not the poll setting. All my battery operated devices 'wakeup' at 1800 and 'poll' at 60 (which means the Vera tries often to see if the device is listening). Inside motion sensors that are hardwired have a 'wakeup' of 60 seconds for more frequent temp updates (to bypass Z-Wave air vents).