Dub will never compete with MAN to the middle and far east because of the huge number of people from that region living in the UK. The number of Pakistanis and Indians living in Ireland is miniscule in comparison. A result of colonialism.
BUT make no mistake DUB is targeting MAN,BHX,GLA,EDI etc for trans Atlantic pax. The pre-clearance is a dream. I've used it several times in the last few years aswell as flying to other parts of Europe then the US, the time saving at immigration in the states is astounding. 25% of EI's t/a pax originate from other parts of Europe that morning westbound. Early morning EI/EIR flights to the UK are set up to deliberately target these people