It'll be interesting to see what happens. It's a tough call. Common sense would say to have it air right after the Superbowl (a la Survivor Australia and All-Stars). Actually, that's more wishful thinking than common sense, but I'd think it would make sense. If football has proven to help TAR since 10 (save for 11 and 14), imagine what the Superbowl would do! Sadly, it's not going to happen. As mentioned, the season would be long enough to start in February and then end in May. Also, with the upcoming Survivor Season, if anything, that's closer to the front of the line of post-SB programs to air right after the Superbowl.
Given that, common sense would be to air it later. To avoid all the conflicts, I think March 14 would be the best bet. It's tough, and only because it's on a Sunday. That's in terms of when best to premiere it. Really, from a tarfly's POV, whatever it takes to avoid having the show end on May 9 is the way to go. That would suck (especially if it doesn't premiere on February 7).
That being said, I don't think 2/14 is automatic. True it would mirror last year's schedule, but things change (like the survivor finale moving up a week this fall). While the Olympics and TAR are on two different networks, that results in TV conflicts & who would want to kick off a season opposite the opening weekend of the winter Olympics? That, and the fact that a couple may feel that their love and time for one another is worth more than any episode of TAR.
I think 2/21 or 2/28 is more likely, but it also depends on the course of the race. 3/14 would be a little late, especially with the ACMs likely to preempt TAR completely before finale time.