but I'll concentrate on the resource aspect from multiple planets in 1 system, but only doing the 5000 words for 1 of those planets. This is not how the rules work. You do 5000 words to take 1 planet, not 1 system. Sure you may control the whole system from a military standpoint, but you can't count those resources towards your fleet without doing the words for each planet.
I'll disagree with this statement here. That is too much like the old rules, where five thousand words for one planet equaled fifteen thousand meters. I suspect that it will entirely depend upon the circumstances present but in most cases I see no reason that a takeover should extend only to a single world within a system. I certainly wouldn't want to do a fifty thousand word RP just for the sake of taking a single planet and say, eight or nine moons that the world has.