Eclipse - Influence action to remove enemy discs?
By the best evidence I can find, no, you cannot remove an enemy influence disc with the Influence action.

You are correct that by a literal reading of the second edition rules, this would be allowed. It appears that this is an oversight that was made when they updated the wording for the second edition. The best evidence would be that the first edition rules do NOT allow this. I believe that ruling the other way would require a statement about this rule being errata'd between editions. But nothing like this is listed in any of the 1st edition errata. It seems that the intent is that the influence space must always be empty.

It's also a good argument that the rules make no mention of removing an opponent's influence disc as an allowed part of the influence action. So if you were to follow the rules completely literally, you would have to move your influence disc to the spot where the opponent's influence disc already is, without moving his. So you would have both influence discs there together.

See discussion on this question here.