If the subfleet ends up mostly on routes at the shorter end of this duration, the lie-flat beds are a bit of a waste.

ATH-LHR is given a block time of 3h55m - though the return LHR-ATH only requres 3h35 - so, using this as the "4 hour" minimum flight time barrier, -or, rather, using the corresponding distance (1510 miles) as the minimum distance barrier, the light-coloured central area of this map (which covers almost all of A3's European destinations) should never expect to see normal, scheduled A321LR service (except maybe during IRROPs and possibly for training/familiarisation flights, though it's not clear that the flightdeck crew would need familiarisation for this new type as much as the cabin crew would need to adapt to the new config and service standards)

If you were to take destinations that require 4 hours of actual cruise time, then presumably all of Europe (excluding Iceland and the far North of Scandinavia, as well as places like the Canaries, Madeira, the Azores etc) is excluded.