I think the default position should be that the member's fund would be retained in the same target date fund post-retirement.
From 66, the default position would be to distribute, say, 0.35% of the balance of the fund every month, rising to, say, 0.40% of the monthly balance from 70. Distributions will obviously vary from month to month but I think folks will understand why that is the case.
However, if a member wants to buy an annuity with their fund, then that should be facilitated.
Equally, if a member wants to draw down the full fund in one go (which would obviously be taxable), perhaps to buy an apartment, then that should also be facilitated.
In my opinion, the guiding principle should be that the State would be paternalistic in establishing the default position but otherwise members would be given the same freedoms as other members of occupational pension schemes.