Dropping randomly from question to answer I came across this answer from which I quote:
Note that vowel muting is a feature of some dialects of Japanese including the Tokyo dialect.
(The linked question and answer deal with whether or not the vowels /u/ and /i/ may or may not be reduced in a given environment.)
The way this is phrased the reverse question immediately popped up in my mind: are there any dialects of Japanese that consistently do not mute vowels?