Star Wars Old Republic will have an endgame

However, they will reveal it in the future. Probably after your 30 day free subscription has run out and there is talk of an expansion because people have level capped their level 80 Wookie Jedis and are bored.

Quotes are from this article over at INC Gamers

" I know some people are worried, for example, about the elder game [and are asking] 'what happens in the elder game, what happens when you get to the highest level?' We do have a plan for that and we will be revealing it the future."

"Don't worry, it's not like we're ignoring that. We have a lot of hardcore MMO players who have like five level 80 WoW characters, so it's not like we don't have the knowledge of what we need to do in terms of the elder game and other aspects of our game."

Whoa really? FIVE LEVEL 80 CHARACTERS IN WOW? Damn that is really really really hard! AMAZING.