I've wondered about the airline's fleet plans and while there could be a lot to be gained in talking to Boeing if they want to get a good deal from Airbus, I don't think Boeing can be dismissed completely. Yes, there's the commonality thing, but commonality isn't much help if aircraft can't do the job they are needed for.
The A330-300 is a fine aircraft, no doubting that, but it's not a long legged machine. So, if EI needs a capacity boost above that 320 seat limit, where does it go? A340s are out because of DUB's runway, so maybe it's worth looking at what the 777 can do.
Boeing knows EI is in the market for new aircraft and that it has ambitious plans; if it can provide a good deal and be a supportive partner in that growth, then perhaps it deserves a deal. Does Airbus have the same incentive to be as accommodating? Doubtful, I would think. The 332 is very popular already.
As for the 332, I have no doubt that more will be joining the fleet, probably an increased gross weight A333 as well, but that's not inconsistent with a Boeing deal; the 777s can replace the 333s and the 332s can soldier on until the 7E7 comes along in 2009.
Just my current thinking . . .