I thought SGA's real tension came from them having been stranded in the Pegasus galaxy with no support or contact with the SGC. When they gave up that plot point and introduced Earth ships that could fly between galaxies, SGA turned into nothing more than an extension of SG-1 with different bad guys.
Not unlike Voyager, I think they could have done more with the show as originally envisioned. SGA could and should have made various alliances, such as long-term relations with the Jenai (sp?) and perhaps founded some kind of alliance against the Wraith.
I wanted to see Atlantis' people having to make tough choices as their food and resources ran out. Instead, contact was re-established with the SGC, and aside from the first season and a half (which I really enjoyed) the rest became a rather pedantic ride. Even the shakeups amongst the cast didn't seem to make much difference in the overall arc of the show.
I dropped the show for a few seasons and only picked it back up when they brought in Samantha Carter as the new mission leader. I'd waited for a long time to see that character get her due... and then they go and replace her with Wolsey!
And Wolsey's character has made the transition from paper-pusher to leader much more easily than he should have. I was expecting tension and acrimony, but like Voyager's seldom-addressed inclusion of the Maquis, Wolsey's entry into the close-knit operation has been nearly seamless.
At this point, I must admit to being really indifferent about the fate of SGA. Perhaps they'll punch up the SGA movies a bit.