I suggest you get yourself a Bank of Ireland Gold visa card - this will get you Aer Lingus lounge access... it's hard to avoid EI exDUB when FR is the major competitor. That's for comfort. Now let's look at status...

If you mostly fly Y...
An AAdvantage card seems like a good idea and some EI fares will continue to earn miles as a partner. But then there's the problem with BA TATL fares. Could be tough to maintain status unless you go to the US a lot.

KL is definitely an option... and AF just serves to increase the possibilities (personally avoid CDG like the plague). However, the rumours of KL's entry to the market with those Avros run by WX seem premature to me. Still AMS is a good place to connect and travelling time is about the same as (and often considerably shorter than) LHR. And KL prices well exDUB.

*A: Just FYI LO is dropping its DUB service in the autumn. And TATL services are non-existant without connecting in LHR/FRA/ZRH/CPH. bmi is a nice airline and good connections are available at LHR. LX also prices very competively and is a super airline. bmi's Diamond Club is very generous in Y - and makes it worth while staying with *A for many in DUB.

We've all suffered in the last few years exDUB, as it is hard to keep one single FF strategy, unless you have a very narrow range of destinations. You have a choice to make: alliance status with good mileage but connections and associated problems OR EI status, direct flights but fewer mileage opportunities and a pi** poor redemption table.

If you travel in premium cabins...
Avoid EI like the plague.
AA still is not stellar given the limitations.
KL/AF still makes some sense.
LH M&M is very generous to the premium flyer, though BD's 55K+ system of doubling miles erodes this quickly for the frequent flyer -you'll need to do the maths to see which might serve you better.

If you travel a mix of cabins, like I do, with some personal expenditure as well as for work, then for my money I'd go with BD's DC, as *G status is easy to retain at 38K and the benefits are useful.

You'll get a comp from most any non*A airline for your JK*G. However, bmi won't typically comp from another *A programme. You could earn you way up to BD*G while running down your JK. Or you could launder your way over by getting a comp with another airline and then comp that over to BD. (beware of this, as comps tend to be a once-off matter, and sometimes the airline wants to see a statement with real activity).

Nonetheless, it never hurts to ask, especially if you point out that you are moving from Spain to DUB, that EI is a load of nonsense - and that BA is the likely winner if bmi doesn't step in... some kind soul with responsibility for Ireland might just see sense (address the letter to Dave Walsh at bmi Dublin )