I think Teal'c had quite a bit of development as the series went along, as did Daniel Jackson. Outside of Hammond, Carter is the least developed character in the main titles, and after eleven seasons being billed as a regular (it says a lot that I forgot her run on SGA entirely) it's just a shame.
Of course, Stargate has gone almost entirely without female writers during its tenure on television (I believe there was one who left SG-1 early in the series), so it's no surprise that the female character in the cast is the one the writers had the hardest time writing for.
Of course, Stargate has gone almost entirely without female writers during its tenure on television (I believe there was one who left SG-1 early in the series), so it's no surprise that the female character in the cast is the one the writers had the hardest time writing for.