Redesigning the 942, if it's not a modular layout, to add the second OTA tuner may be a major redesign. Logically we think, just plug this item in and viola we are set. Electronic layout requires that there be significant testing to ensure that the added components do not interfere with the existing ones, etc.
So if we say the "hardware is there now, its just getting the software down", this picture will change with a hardware redesign.
For those that want a 921+, essentially a 942 with the extra OTA interface and the ability to output HD/SD off of either output should look forward to a 943 or some other model. E* could make this extra feature product available at a premium and offer an upgrade for all existing 921 users if the existing 921 problems are not quickly resolved. This would allow them to have a HD DVR for the low cost market and an HD DVR for the high-end that would/could replace the 921 system.
Of course any HD DVR they release should support the new MP3/Slide show technologies they previewed at the summit. Eventual support for some type of external capacity upgrades (ala external HD) should also be pursued. There should be some type of device that meets consumers needs as well as satisfies the "content protection" needs of the copyright holders at some point. If the full USB 2.0 spec is fully supported in the new 942 and other *4* series products, the ability to software engineer support should be possible as a future upgrade.
For the high-end 921+ (921 upgrade or replacement), make sure that the USB 2.0 and the IEEE 1394 ports exist in full "hardware specs". Again the software doesn't need to be enabled, but be a possibility as soon as the "content" issues are resolved. If this is clearly communicated to customers from the get go, it would still be a marketable feature that could be looked forward to.
Anyway, that's my suggestions. I'm sure others may or may not agree.