Probably too late for the very hard mid-December deadline for those losing their insurance, maybe too late for getting enough young healthy people enrolled before adverse selection forces insane 2015 premium filings from insurance companies, which are due by the end of March.
They also have only 4 well functioning states' systems to chose from as I understand it.
The centralized subsidy calculation/verification/etc. process, which the Federal system does for all the exchanges is another issue, although I've only heard that some time ago is was known to produce incorrect results under testing.
Also would require the Federal government to admit a much bigger screwup than they've been willing to so far, in a process entirely driven by politics (http://www.washingtonpost.com/politics/challenges-have-dogge...) until the last week of last month when CMS was fired and the fix-it czar was appointed.
If you've been in this game long enough you've seen projects and companies destroyed by a failure to take decisive action when it could have made a difference (or read, for example, Churchill's The Gathering Storm, or any shorter version of how WWII could have been so easily averted by preventing German rearmament). The odds are pretty high this is going to be another example of that.