I’ve always had a soft spot for Citaros, however I do agree with you. Arriva also seem to be standardising a lot of fleets with Pulsars so it would make sense in the short term.Just some more Pulsars to see off the Max Citaros would be good, despite not exactly being modern, the Pulsars are a much nicer bus from a passenger point of view, I really don't enjoy the Max Citaros.
In the long term they would benefit from new buses!