I like to think of SGA as a group of explorers that had to become very successful scavengers, just to be able to survive. They came across a couple ZPMs before finally getting their hands on me through the SGC, and they were still trying to find more efficient sources of energy to power the city, and then they drain their only ZPM.
Then, they manage to take back the city, and have at least one ZPM after that, but they drain it trying to escape, and steal another one to survive.
All the while still maintaining trading relationships with various other groups of humans in the galaxy, and helping them against the Wraith.
I agree however on Amanda Tapping's role in SGA. Her character has become less technologically capable than as it was back in SG1, but at times she has shown she's still got some mad skills.
I hear though that in season 5 she'll be more of a guest star as Robert Picardo's character becomes commander of Atlantis. And I hear that the character of Dr. Carson Beckett might make appearances in season 5 as well. He's going to be making appearances in season 4.