I'm normally not a user of office programs, still I fired it up to see how Office is affected if 30-metric-aliases.conf is removed. The relative merit of "uncorrupted documents" vs "good looking hinting" has to be clear here.
So I made a series of tests:
reference: A line of WWW before page break, a line of MMM after page break, all in _Arial™_
1. Arial installed, Liberation installed
2. Arial removed, Liberation is aliased
3. Liberation removed, Nimbus Sans L is aliased
4. 30-metric-aliases.conf removed, DejaVu Sans is aliased.
Hang on, the results don't support your argument, but they show that 30-metric-aliases.conf does not do what it's supposed to achieve. Hence, it could be deactivated, unless Liberation is installed by default.