Why not cap the relief for investors at the same level as the cap for residential buyers? A fairly simple and not too drastic approach to even out the playing fields and help some FTB's to get a foot on the latter. Why not increase the threshold for the rent a room scheme in line with rental inflation each year - this should take it up €10k or €12k now - Allow an FTB to rent out 2 rooms without risking going over the threshold.
I've seen two 30-something family members 'emigrate' (one down the sticks, one down under) in one month as a result of their inability to buy a half-decent house in Dublin. We can't allow the current situation to continue.