This is in danger of going OT for the BA board (except that we all use these ex-DUB flights in J nowadays!), but here goes: I've been watching this route like a hawk since I'm booked on it around Christmas. The DUB-PHL the weekend before Christmas looks like it will almost certainly be a 330. I'm still worried about the return, though.

The explanation I've seen on the AA board is that under the new management, the merged AA/US is likely to be much more aggressive about matching planes to demand. I think everyone's holding their breath until late October when the two carriers formally start operating as one.