Death Star II

Before being banned on SDN I have recieved lot of complaints why Federation should not be able to destroy DSII. Microconduits... which we never saw used by Empire. It was also argued that conduit throught which Rebels flew inside was to be removed after construction was finished... which is, to say at least, ridiculous, as seen from following screenshot.

Folks at SDN argue that it was impossible for Rebels to destroy Death Star II after it was completed and that it was main reason why they attacked it. Wrong. Main reason for attack was fact that Emperor was going to be there. Secondary reason was promptly displayed when DSII destroyed cruiser Liberty. Superlaser of DSI was unable to target capital ships.

Also, much simpler solution would be to just put chimney caps. Constructing thousands or millions of micro-exhaust ports with each being over 90 kilometers long (due to zig-zag structure of vents) would be engineering and logistical nightmare, not to mention that construction would be delayed enough to make canon timeframe impossible.