This is because the 767-400ERs were previously used on domestic services and didn't have an international business, like the 763s do. Frankly, I thought DL might use a 763 to DUB, which one would expect to be a pretty lucrative route from a business perspective?
Incidentally, don't the first two EI 332s come up for D checks pretty soon (I think 'EWR was delivered in 1999?), in which case one would that they could be refitted with up to date IFE/seatback TV at that stage.
On the subject of new aircraft, while the A332 is "only game in town" at the moment - i.e. in terms of aircraft available right now, rather than 2012 - I see Aeroflot has "cancelled" an order for 22 787s, with BA and SIA apparently chasing the slots. While the 787-8 is the smallest of the family, it's by no means a small aircraft; while slightly shorter than the 332, it is wider. QF's Jetstar subsidiary is using these in a 2 class (premium economy/Y) on its new services, in a 303 seat layout. I'm sure EI is actively considering all options, but just for the sake of discussion ...