Just read an interview on Newsarama with writer James Robinson about his current stint on the Justice League of America.
In case you haven't read his run yet, it is absolutely dreadful, and it features the WORST JLA lineup (the Dick Grayson version of Batman, Donna Troy, the "disco" Starman and Congorilla ... that's it!) since the Detroit iteration back in the day.
Anyway, I was reading the interview and Robinson said something that really struck to the heart of the problem with the title:
"One of the things about this book is it's always going to feel like it's right in the heart of the DC Universe."
That's an erroneous way to approach the book and is one the reasons why the teams roster changes so much. By trying to tie it so much to current DC continuity — which is always shifting and moving — then the book is sort of handcuffed by the whims of dozens of different creators on a bunch of divergent comics. So if Superman is in outer space for a story arc in his own book, then he's missing from the JLA for just as longer ... maybe longer. (The worst example of this was during Dwayne McDuffie's run not too long ago.)
And make no mistake, the JLA is DC's "Big Seven" — Superman, Wonder Woman, Batman, Aquaman, Green Lantern, Martian Manhunter and The Flash — and any change to that lineup is merely an aberration that can't last long.
Now, I'm not saying the JLA should totally avoid continuity. I'm just saying that the team's adventures work best when they take place between story line's on the individual members' own books — not during.
That's my take.