It often appears in the literature that the full quantum gravity theories are plagued by the quantum field theory problems, specially non-renormalization. And they also state that in the context of quantum cosmological models in minisuperspace setting this problem of non-renormalization can be avoided. Is there intuitive or mathematical reasoning for realising as to how these minisuperspace models are renormalizable?
By a minisuperspace model, I mean where all but a finite number of degrees of freedom are frozen.
I have seen this arguments in two different works
Time and the interpretation of canonical quantum gravity
William G. Unruh and Robert M. Wald
Canonical Quantum Gravity and the Problem of Time
Chris J. Isham