Having flown on AG, AH, AI and AJ for that matter, I personally think they are spot on. If however they can trade them in/offset them for some newer 737/800's, then that sound good to me. No Cat III issues on 32 at LBA in Winter, less maintenance and fuel costs I would imagine, and increased load factors when filling a 186 seater instead of a 238 seater.
I must admit that it is rare I see a 757 come in with much more than about 190-200 punters on.