I would certainly have preferred the 787. My big concern about the A350 is that it's still an eight abreast aircraft whereas the 787, with a wider cabin, can be operated in a 9-abreast configuration, should EI wish to go down the long haul low cost route. The principal concern is that FR has signalled its intention to go down this route and if they were to do this, being a 738 customer already, the 787-8/9 would almost certainly be their choice and having discussed this on the Orders yahoo-group, the 787 at 9-abreast would kill the 350 on costs per seat/mile.
That said, the A350 will be a better aircraft than the 330, which is already a superb aircraft, so while one can argue that it's a warmed over A330, it's still an improvement on an already very good aircraft and it's one which will serve EI very well indeed. It has a very healthy range and even if it can only be operated in an 8 abreast layout, its economics will still be pretty impressive just not quite as good as the 787.
One point to bear in mind, however, is that even if EI were to go Boeing, the 330 would still be a preferable interim aircraft to the 777, which EI may regard as too big. The proposed A330-200 deal, regardless of whether Boeing or Airbus is chosen, will most likely be a lease for about 6-7 years, rather than an outright purchase, so it doesn't preclude a 787 deal.
I still think the 350 will get the green light; Boeing had a very good year last year and by all accounts (with the 787 likely to win at SQ next month and at EK - long expected to be a 350 customer - later in the year) this year will be good; the 350 has had a less good year and Airbus will be particularly keen to get new airlines on board; losing EI won't upset Boeing too much and they may not feel the need to offer EI a "killer" deal. Losing EI would be a lot more damaging to Airbus. Remember, it's not just the value of the deal but the fact that a 320/330 operator has dumped the 350 and the impression this creates.