1. I'm not sure what your meaning is in question number one.

2. I don't think that notation is necessarily at issue with the many people who simply don't and won't like chant. They don't like the sound of it, regardless of the notation. They may facetiously pick out the visible notation as something strange, but the truth is that they just don't want to sing it or hear it. I've heard, actually, more resistance to learning chant notation from trained musicians than from those who don't read music. These latter have often allowed as how chant notation is easier than modern notation. We introduced Credo III in chant notation to the congregation at Walsingham last Sunday. This is not an easy chant and it has a very wide tessitura, but our people were reading it and singing it. Now we can say good-bye to singing the creed recto tono! My only regret (and I really do regret it) is that it was decided to use credo III instead of credo I, which is the only one ever sung at Sarum. Credo I is the Sarum creed and is the one that we should be singing in the Ordinariate. But, at least we are singing it!!!

More about notation - at Walsingham we have an early 8.00am mass which is all chant, including Gregorian propers in Latin. The people sing the ordinary in Latin, reading chant notation - and they do so heartily. Congregations can sing anything they want to - depending on attitude and confident (and determined) leadership

The concerns which you have are, I think, best addressed with attitude, not with ability.

3. This question is perplexing. I don't believe that tempo is a factor in chant. Different chant has different tempos, just as modern music does. You may be correct, though, about the melismatic chant. This chant should be weighed carefully by those who are introducing chant to the congregation. Some congregations will be more experienced or advanced or talented than others. As a very cautious rule, melismatic chant should be avoided for most congregations.

Some background from a 2010 discussion on these boards:

https://forum.musicasacra.com/forum/discussion/3193/gregorian-chant-is-a-decadent-enchantment/p1

1. Chant makes no sense in modern notation. Many nuances are lost in the absence of neumes. On the other hand, it begins to make MORE sense when the notation studied is even earlier. See: Graduale Triplex, Graduale Novum. Solesmes today does not even use the method often referred to as the “Solesmes method” because of their continued studies and development of their approach.

2. Notation is not the issue. Many congregants do not read music at all, whether modern or Gregorian notation. I have had congregations chant successfully from square notes in 4 Novus Ordo communities:

-an impoverished Catholic school
-a poor urban Hispanic parish
-a large and wealthy suburban parish being weaned off of contemporary / Christian rock
-a small neighborhood parish led by a tradition-friendly pastor

In all of these situations the parishioners who wished to sing did so with no issue. The only explanation ever needed was once when the secretary of the wealthy parish asked me about the notation. I told her that for her purposes it’s all the same: up means up, down means down. And the notes are square instead of round. She said “ok” and that concluded our conversation.

3. I have never heard a complaint that someone hated chant because it was too fast, but often hear the opposite: it is slow and boring. Melismas are not the problem. Many chants of the Kyriale (Ordinary) are quite melismatic and easily followed by a congregation. Perhaps this is by design: the Ordinary of the Mass is really all that the congregation is tasked to sing. The long melismas of the propers, especially of graduals and alleluias, are for the schola and cantors and a personal ability to sing along should be of no concern to the congregation. I would have no interest in trying to get a church of 500 to sing last week’s introit Da pacem together.

https://youtu.be/-_ovA4Z5-ss