I doubt anything major changes about BOS - it doesn't make sense to me as potential hub given the fortress at PHL for mid-atlantic and northeast connections, CLT for the south/southeast, and JFK for the premium intl traffic.
Besides that, BOS is already competitive. Look at what UA and DL tried to do for two years on AS's BOS-SAN route. When I fly it later this month, it'll be the first time I paid more than $198 for it. Going to a focus city with the number of non-stop destinations as B6 probably doesn't make a ton of sense, but competing on some of those routes where they think they can sell some premium cabin space does.
I'd still love to see PWM get AA service to ORD, DFW or JFK, though!