Since the last papal reform, several proposals have been offered to make the Western calendar more useful or BLANK. Very few reforms, such as the rather different decimal French Republican and Soviet calendars, had gained official acceptance but each was put out of use shortly after its introduction.
Options for BLANK:
I am unable to understand the difference between uniform and regular in this context.
By understanding their meaning and the context of use as adjectives I found these below meanings.
regular: Having a constant pattern
And choose uniform because it made sense to me.