In January 2014, Lucasfilm essentially axed the entire Star Wars Expanded Universe, sweeping it all aside in favor of its new, more singular canon leading into the new movie trilogy and side projects. Like the rest of the EU, Star Wars: the Old Republic was slapped with a 'Legends' imprint and sent on its merry way, and quite rightly the fans worried that it meant doom for the BioWare Austin MMO. Almost a year later, SWTOR's status has become an increasing question of debate as the new movies approach and the announcement that there will be a Cantina Tour stop at Star Wars Celebration in Anaheim, CA.
SWTOR has the unique position of being practically the only ongoing Star Wars project that is explicitly EU. As soon as the balloon went up last year, all previous EU stories, books, games, toys, etc. were put on hold or otherwise quietly submerged in favor of the new canon. Most of the things you can find on the shelves in toy stores these days are leftovers or stuff that's expressly movie or Clone Wars-related. You can also find some Rebels things too, but that's their new push.
Let's be real here, some of the EU stuff was pretty terrible, but then again, there's a rather large segment of the Star Wars fanbase that wishes characters like Jar-Jar Binks could be nuked from orbit rather than remain canon. Still, it's not unheard-of for things in the EU to be canonized by appearing in the movies or in Clone Wars. We all know that the name Coruscant was a Timothy Zahn invention that became canon the first time Qui-Gon Jinn casually mentioned where he and Obi-Wan were taking Padme and her gaggle of decoys, and fan-favorite EU character Quinlan Vos has appeared in Clone Wars.
Now, let's take a look at the pros and cons of being labeled as either canon or Legend.
Since its creation, the Lucasfilm Story Team has been listed in the credits of SWTOR starting with Galactic Starfighter. These are the folks like Keeper of the Holocron Leland Chee who straddle Lucasfilm and Disney. Every single Star Wars release has always had to be approved by Lucasfilm. It's no secret that Lucasfilm gave BioWare Austin a pretty loose rein, and that BioWare Austin made a point of not taking things too far out into left field to avoid Lucasfilm tightening that rein. The Old Republic era is a fairly cohesive whole, ranging from the old Tales of the Jedi comics, Knights of the Old Republic the game, and the Zayne Carrick comics written by John Jackson Miller. Each of these predecessors are reflected at some point in SWTOR, and there are many, many references to the movie era in the game as well. The fact that it's over 3000 years before the movies and official canon means that things can and will change (hello, Korriban).
So, what about if the game always remains under the Legends imprint? The obvious pro to this situation is that while BioWare Austin can dip into the lore and art style of the upcoming movies and even Star Wars: Rebels, they're not married to it and can occasionally go off the rails (unlike PVE space combat). It doesn't actually matter if they publish something that is contradicted by canon. Sure, some people might get confused or upset that suddenly their favorite character is missing or different, but in the larger scheme, it's like it's always been during old-school days when we had six levels of canon. We hand-waved those faster than 'these aren't the droids you're looking for'.
The freedom to explore new planets, new races, and come up with new lore that's not tied to the canon is quite exciting. Being a fiction writer as well, I derive far more pleasure creating my own toys than I do rehashing someone else's story, even within an existing intellectual property. I've never heard any past or present BioWare Austin writer act in any way other than to be massively excited to get to work on Star Wars. On some level, it will also give Lucasfilm a bit less impetus to squelch anything that doesn't firmly meld to their official canon.
The con, of course, is legitimacy. In many ways, there are some who believe that the lack of an official canon stamp means that suddenly the Legends imprint items aren't real. However, just like how the JJ Abrams Star Trek movies in no way suddenly caused all the previous iterations of Star Trek to vanish into a black hole (even if we might wish that fate upon the abomination that was Star Trek V), the same holds true for the EU, SWTOR included. While it's harder to find the comics, books, and toys, they still exist. I think the biggest concern is less that the game is Legend status and more that it's now lumped into the overall contract that EA has with Disney. If you think about it, a separate contract meant that the game itself had a specific contractual shelf-life irrespective of its success or failure. Now, it's part of a multi-game contract that probably has no specific guaranteed timeframe for SWTOR beyond 'if you make us money, we'll keep you around'. I'd be very surprised if any dates were codified in whatever contract was eventually signed beyond the overall date covering the whole nine yards.