A couple days ago, WoW announced that they are going to announce their new expansion at Gamescom. It just so happens that they are going to announce it right after they report their subscription numbers, which are almost certainly going to be down. This led to some talk about how it will affect SWTOR's expansion plans in October.
I really don't think the two will have any affect on each other. Blizzard may be announcing the expansion, but the odds of it happening this year are quite low. They usually take a year after announcement to release the expansion. So while the Gamescom hype may go to Blizzard, it will subside once October rolls around. BioWare already announced Fallen Empire anyway.
More importantly, WoW and SWTOR are very different games, more so once Fallen Empire comes out. WoW will add X Raids, X dungeons, and a load of mostly uninteresting quests which are just used to level the player. SWTOR won't be releasing new group content at the start, instead concentrating on the questing/story experience and making existing content relevant for everyone. So, I think they have different audiences now.
And playing SWTOR isn't an all or nothing affair. With the new episodic approach, they can take a couple months off from SWTOR to play WoW. Then, come back, pay $15 and get everything they missed. I don't just play SWTOR (although it is my main game), and I suspect a lot of people are the same.
Plus, Star Wars.
Merry Christmas and Happy Holidays
16 hours ago