The wind of arrogance blows through this thread........
Accidentally changing parts of the text because of hearing problems of one kind or another is normal and we all do it. The main thing is that the story is unchanged.
Whether a song is good or bad is a personal decision. Whether a song is historically correct or not, and how this may or may not affect the story being told as a whole depends upon how pedantic you feel you need to be.
Changing the text because you think that your 'improvement' is what the composer actually had in mind because it suits your linguistic hang-ups smacks, I hate to say, of arrogance. Or have you had the politeness to get in touch with the composer(s) concerned over the matter? I have, in the course of the last 40 years or so, written a few songs and I have, now and again, excercised my right to make changes to them. I know of some people who changed some lyrics because they were trying to transcribe from old cassette recordings they'd made under lousy conditions. The stories weren't affected so that was OK by me.
However I would jump on anyone deliberately changing my lyrics because they think they know better than me what I had in mind when I wrote them. If I construct and formulate parts or all of the text in a certain way it's because I specifically want it that way and my response to anyone deliberately changing parts of the text would be,"Just who the f*** do you think you are??"