I think there should be one more "as" phrase to make it comparative, so I think "as it comes now" is omitted somehow. Is the phrase "as it comes now" omitted somewhere?
It is not necessary to add an extra "as" in this case, you can read it as "I would've been just as excited if it (had) came out late 2003." Comparative situations require two "as"es, but this sentence is an exception and does not require two. In this case, it is also possible to add an "even" so it reads as "I would've been just as excited even if it came out late 2003." You can see similar examples of this pattern below. Ex: My birthday party was very fun. I would've been just as happy even if I didn't get any presents. Ex: I would've been just as happy to receive a pencil as I would have to receive a car.