When I worked in Dublin City centre, I would often see the queues outside the old Passport Office on Molesworth Street during the summer months. Invariably it was the late-teens/early twenties brigade realising that they actually needed a passport to travel to Santa Ponsa for their week in the sun. Never any queues at other times of the year.The backlog will be cleared by the autumn. After that just submit in January/February when it's quiet.
April-July is always peak season as people wake up and realise they have to go on holiday.