The problem with Old Republic wasn't that it was a subscription game and the whole "Oh, this is a the era of F2P" talk is just that: talk.
This is not to say they won't improve their numbers by going F2P (and dropping the price of the game to $15, that won't hurt either folks); that's actually fairly likely. But, the bigger reasons why they're in this position are the same ones that every other "WoW Killer" has fucked up in the last half decade or so and the fact that none of them learnt from their collective mistakes - even more-so when you consider that Bioware is considered to be top tier - is kinda surprising. That said, since they seem to be unable to learn on their own, lets explain it to them:
Lesson The First:
Your game must be finished. Yes, yes, these games are never "finished", but the days when you could launch with a leveling experience and some dungeons and: "we'll tack a proper endgame on in 3-4 patches", are gone. Your benchmark now is a WoW Expansion because the simple reality is that people are going to level to 50 in 4 days regardless of how grindy you make it, kick around your dungeons a bit, and then go "well, nothing left to do here for 8 months", and then walk out the door taking their friends and negative word of mouth with them.
In case you haven't noticed, they don't come back in great numbers either because the next new shiny is right around the corner to pull their attention.
As such: Endgame. Level 1. Must. Be. Finished. At. Launch.
Old Republic made an attempt at this, but in making everything heavily story driven they were limited to one Operation and 5 bosses. That's a shortage of content that's going to be ground into dust in short order.
Likewise, while no software is ever bug free, you've gotta nail those game killers. Old Republic lost a friend of mine when they were doing the final quest for their class, got half way through one of the events, and then the whole thing bugged out; placing them in a position to start all over again.
I shall quote: "Fuck That".
And, out the door they went.
You've got your 60 days folks: get yourself off on the right foot or it's all for naught.
Lesson The Second:
You can have too many servers. The one thing we've learnt from all the "WoW Killing" (1 2 3) that's been attempted over the last few years is that there are at least 1 Million players you can count on to try something new. Old Republic was able to leverage their license to 2 Million. Then half left and most of the servers became ghost towns.
Sometimes I think developers get too excited when they see a whole pile of initial subscribers so I have a bit of advice for them. The trick to a new launch is now as follows: enough servers that people can play, not so many that when the inevitable happens and folks bail your MMO turns into a single player game most nights. Hell, sometimes people complaining about how hard it is to get in is a good thing if it results in a general feeling that people are playing the game en-masse. Even WoW is having to make concessions to the reality that not having people to play with provides a disincentive to continued play via cross-realm zoning; a change that could allow them to eliminate the concept of "server" altogether if they wanted to.
Side note: If you're a competitor working on the next-next WoW Killer, don't be surprised if Titan comes along and doesn't have "servers" at all. Cross Realm Zones is as close as you're going to get to an advanced warning.
So, if you want to avoid server merges on the principle that they make your game: "look like it's dying", don't have too many servers to begin with.
Lesson The Third:
I think the big lesson is that trying to "kill WoW" is pointless.
This is more a conceptual problem for fanboys, investors and media than the developers themselves; they've likely some idea at this point that this is unlikely. I'd suggest WoW's more likely to kill itself than be killed. It's approaching 10 years old, people's /played is getting up there, and general life changes for folks playing since vanilla and are now almost a decade older are going to move them along into other interests with no intervention required from anyone else.
To a certain degree, this is why Blizzard is working on making the game more accessible: the 24-28 year old with work, significant other, and potentially kids to wrangle is harder to lock down into the stock raid night login pattern than the 14-18 year old they were when they first logged into the world and this is even more true for those who are older than that. So, they need to find ways to keep those players involved and feel like they have a reason to log in with the limited free time they may have. In this way Blizzard keeps their community involved in the game, even if they're not digging heavily into the endgame, and it's that community of friends and links that keeps the game at high levels of subscription - even after the drop-offs - and helps to attract even more new people to the game by keeping it in the public eye.
The hardcore may bridle at it, but it's these concessions and new things to do on the side that are likely to keep the game alive.