I doubt it will. Lots of stations have sub-channels so 1080i and even 720p reception suffers. I'm not sure even if a station had no subchannels that 1080p would be as good as it could be with only about 18 mbps to play with. Now with mpeg-4 sure. But no TVs have mpeg-4 tuners and no stations have mpeg-4 equipment. Seeing how only 10% use OTA I'm not sure there's enough motivations for broadcasters to use it. Plus they would probably wait until mpeg-4 tuners became widespread which would take maybe 6-8 years if they started including them today and there's no evidence to show they are going to do that anytime soon. Seeing how the FCC is intent on killing off OTA I seriously doubt you'll even see mpeg-4. That's a shame because with mpeg-4 you could have 2 possibly 3 720p/1080i HD stations on the same channel. That then would help free up bandwidth the FCC wants so bad for broadband. I however haven't seen anything on the FCC mandating mpeg-4 tuners in TVs nor anything about helping stations upgrade to mpeg-4 equipment.
Yes the spec NOW has it. How many TVs have ATSC tuners with the new spec? NONE that I know of. As I said even if all TV being sold today had that new spec it would take years before stations would broadcast it. You don't want viewers to not be able to watch your channel. I would imagine they would want to be sure at least 90% of TVs in homes had this spec before broadcasting in it. That would take 8 years in my book. If the FCC starts pairing TVs channels down from Ch 51 to Ch 31 and force stations to start sharing channels they wouldn't have choice but to use mpeg-4 if they want to broadcast in HD. But they certainly wouldn't be able to do 1080p that way.