A YYZ service would reduce pax on the DUB-ORD route, which would mean the additional 4 weekly flights operating this summer, wouldn't be needed.
Reducing the ORD service will then defeat the Hub at DUB. Only this summer is the ORD schedule allowing decent connections. The new 05.25 arrival and 15.45 departures are what is needed to offer similar service like they do to JFK and BOS. ORD was the only destination behind. Connecting traffic through DUB is very important to Aer Lingus and removed ORD flexibility would be a bad move and as a SFO service couldn't many connections bar London and a few other spots in the UK. significant risk in restarting SFO and reducing ORD and EI only said when the UA reports surfaced that SFO wasn't in the plan short term. Anyway I am sure that Mueller will make the right decision at the end of the day.
The 757 could operate YYZ 4 times weekly, and operate ORD 3 weekly if they wanted to keep the connections through DUB. Or they could use the 757 to operate the extra ORD rotations on a daily basis? Either way, the 757's add a lot of flexibility to the fleet, create a great low risk opportunity to open new routes, and can help further develop Dublin as a hub