Imho what SGA needed was less Rodney and a lot more focus on the other characters. I didn't follow any behind the scenes stuff on SGA, so I don't know about that, but there were a lot of things (Michael, yes) where I thought; wow, didn't they learn anything at all?

And yes, amen to all you said - they could have done wonderful things with Sam at the helm, but they left a lot of that potential unexplored. I still loved her on SGA because she was allowed to step out of Jack's 'shadow'.