(1) The extra commerce doesn't effect you until your cities reach a certain point ( pop7 I think)
(2) Hoplites are great as long as you have Iron near by
(3) Lowered corruption is good
(4) The most useful science buildings arn't till the middle ages. The Science wonders (Copernicus, etc) might allow other civs to catch up to you in science if you don't lock these up.