A big player can annoy smaller players(that doesn't mean less active players) by attacking them with huge fleets.
Big player got two benefits over here:
1) He got a big fleet, and the defender needs a lot of defence to cover himself
2) The big player is high ranked, which counts in a game like planetarion
And one negative side:
1) The player is big, he get cov opped constant
A small player(that doesn't mean less active) can cov op a bigger player
Small player have one benefit over here:
1) He reduce the gap between him and the big player(Although it needs a lot of cov op to close the gap), the big player can arm himself against cov op(about the same as a small player can defend up to a big player). Security centers ain't working good, but a small vs big fleets sucks as well
And the negative side:
1) This dude is small, low in ranks and often not rewarded as much as the big player.
So we got 2 kind of active players. If you are big you get credit, and have a HUGE advantage when attacking, if you are small you got no credit and have HUGE advantage when cov op big players.
So, for the people who are big and active: You got a much easier life then the small guy without credits.
And for the small and active people: Credit for you, pissing off every big player out there!