HDMI 1.3 connections and HD audio decoder chips are commodities at this point; i.e., manufacturers don't have to re-invent them, just buy them from OEM parts makers. So that's certainly not holding Lexicon up (they demonstrated they can do stable HDMI implementation almost 3 years ago on the MC-12HD).
From the cryptic morsels posted by Lexicon reps at SMR Forum last year, seems there were/are two things delaying the new platform. First, everything was put on hold as Lexicon moved from Bedford, MA to the giant Harman campus in Northridge CA. Second, they're apparently working on some sort of "re-boot" of LOGIC7 (their words, not mine). Typical of the company, they wouldn't drop any further hints.
Lex processors were converting 2.0 and 5.1 to 7.1 in the mid-1990s. This capability wouldn't become ubiquitous until PLIIx was released almost 8 years later. Just adding HDMI 1.3 connectors and internal decoding of the new codecs should be the least of Lexicon's concerns, since it would just give them another "me too" product. What would be the point when you can get those same features elsewhere, and for less money?
Proprietary surround processing, bass management and room correction has always separated their processors from other pre-pros in the past, as it probably will in the future. Whatever processing they're working on, I hope it's worth it. Time will tell.