I don't understand what you want. If you read your own post you will see where Shoghi Effendi said it is undignified.

You are right. Times change, but there is no justification for now going from door to door. Shoghi Effendi said it is undignified and that's why we should not do it. His interpretations are authoritative.

As you said, Ruhi should just be one tool among others. The reality, however, is that we neglect everything else. Only the core activities seem to matter. People either do the core activities or they have already been discouraged by what is going on within the Bahai faith and decide to be inactive. The regional conferences were supposedly for the whole Bahai community. But by focusing only on the core activities everyone else, who prefers a different method of teaching was excluded.

I have been puzzled by something a member of the International Teaching Center said at one of the conferences. I know that the UHJ wrote "the institutions of the Faith will continue to respect the wishes of those who, for whatever reason, do not feel inclined to participate in the study of the books of the Ruhi Institute." But why would a member of the ITC who comes as their representative say that it is a matter of obedience that everyone participates in an intensive program of growth? This implies that everyone who doesn't do it is breaking the covenant.

I think we overemphasize the importance of the core activities. We want unity in diversity, but this leads to uniformity. In 1988 the UHJ said the following in response to a teaching project in Japan, "This does not mean, however, that there is any particular system of teaching which individual Bahá'ís should pursue. Different cultures and types of people require different methods of approach. While taking the fullest advantage of a workable method in one area, the friends should be open to other methods and not blindly insist upon doing the same thing everywhere." I agree. Just because some people feel comfortable with the core activities and Ruhi it does not mean that everyone does. This way we will never reach entry by troops.

I don't have that much of a problem with the Ruhi books (as long as it is completely voluntary, and there is no pressure). Even though people might get the impression that I dislike everything about this institute course, I believe it has potential. There is no doubt that it has helped a lot of people to know and understand more about the Baha'i faith and to apply the teachings to their life. But the way the books are being used is inappropriate. I think it is wrong to use Ruhi to teach. I have never been able to understand how it is relevant for someone, who does not believe in Baha'u'llah, to learn how to teach, do home visits, etc.

In Ruhi book 2, page 26 it says:
"How sad it would be if today someone were to hear the glad tidings of the Revelation of Baha'u'llah, but accept Him not and decide to follow the traditions of the past. He would join those who in every age have hoped for the coming of a Promised One, but when He appeared, have rejected Him and, unfaithful to the Eternal Covenant of God, have clung to their own superstitions."

Please tell me how a Bahai can justify inviting non Bahais to a study group and then basically tell them that if they don't follow Baha'u'llah they are superstitious and unfaithful to God. This is clearly contrary to Baha'u'llahs instruction to teach with "wisdom and eloquence."

Another problem is that some parts are manipulative (Ruhi 2, p. 23, paragraph 2). This is not everything; there are many more issues with the contents and the methods.

You seem to believe that success in the process of entry by troops depends on how well we "cater for large numbers" and on how sophisticated our system is. Then what do you think about the following quote:

"Not by the force of numbers, not by the mere exposition of a set of new and noble principles, not by an organized campaign of teaching — no matter how worldwide and elaborate in its character — not even by the staunchness of our faith or the exaltation of our enthusiasm, can we ultimately hope to vindicate in the eyes of a critical and sceptical age the supreme claim of the Abha Revelation. One thing and only one thing will unfailingly and alone secure the undoubted triumph of this sacred Cause, namely, the extent to which our own inner life and private character mirror forth in their manifold aspects the splendor of those eternal principles proclaimed by Baha’u'llah" (Shoghi Effendi, Baha’i Administration, p. 66).

Now an answer to your question about the cause to the symptom. We were not supposed to put so much emphasis on converting the masses in the first place. The main reason why large numbers of people will eventually enter the faith will be the result of our effort to apply the teachings to our lives. I think any direct effort to convert the masses is doomed to fail. This active approach to cater for the masses leads inevitably to too much emphasis on the quantity. The only difference between now and the 70s is that we know that mistakes were made. We are looking for a solution. We tried to work on the quality. Nevertheless, the number of new believers is still a criterion to measure the success. I fear that even if we are able to convert a lot of people many will leave the faith after a while or become inactive.

The UHJ says that we have learned from the 1970s when we were not able to cope with the masses. Ruhi is supposed to be the solution to all of these problems.
I don't think we were able to recognize the actual problem. In fact we are making the same mistake as we were during the 70s. A lot of people who joined the Bahai faith left it.
The problem is that our approach did not have any substance and this has not changed. The fact that Bahais did not follow up with newly enrolled believers is not the cause: It is just a symptom. The term "mass catering" describes the problem very well; so does Groovers fast food franchise analogy.

Entry by troops... I think we are expecting it too soon. Already in 1977 the UHJ said that "entry into the Cause by troops has been a fact in some areas for a number of years."

Sen McGlinn posted an interesting analysis on his blog: Entry by troops (time to be announced).

Do you think door to door teaching is a legitimate tool, because of what the Universal House said in the letter? Do you think the UHJ is Infallible and that's why it can't be wrong even if there is evidence that Shoghi Effendi said that people should not go from door to door?
Do you think that I misunderstood Shoghi Effendi's letter, and how this relates to his infallibility and authority he has within the Baha'i faith?
I am just curious.
I am ready to change my opinion if anyone can use Baha'i writings to prove that I am wrong.
What I have seen quite often is that as soon as there are good and rational arguments about something like this (that the Guardian prohibited door-to-door teaching), Baha'is who believe in the absolute infallibility of the House just ignore them. But I think that I can expect the followers of a religion that is "scientific in its method" according to Shoghi Effendi (Letter to the High Commissioner for Palestine, June 1933) to give me good arguments for every claim they make. In the Kitab-i-Aqdas Baha'u'llah says that when differences arise we should refer to the Holy writings (53). I try to back everything I say up with authoritative texts. I expect others to do the same.
Now back to the issue of Infallibility. In the article Infallible Institutions the scholar Udo Schaefer argued for a restrictive interpretation of the infallibility of the Universal House of Justice that is limited to its legislation. So far no one has been able to refute it. Some have said this argument is untenable. No one has managed to say what exactly is wrong about it. Unfortunately most Baha'i scholars have never heard of hermeneutics---the study of interpretation theory. People will usually refer to a passage in the Will and Testament of Abdu'l-Baha that whatever they say is of God. The problem is that you can't just take one sentence that has been repeated several times in different authoritative writings and say that this is everything there is about an issue. Dr. Schaefer considered all the passages that could give someone the impression that the UHJ is completely infallible. He analyzed all the Bahai writings as a whole and their relationship to come up with the argument that the Universal House of Justice is only infallible in its legislation.
I would like to stress that the issue of the infallibility of the UHJ has "no relevance for the legal authority of that supreme body, which derives simply from the fact that it has been ordained by Bahá'u'lláh" (Schaefer). An example of this is if the UHJ tells me to stop commenting on the door-to-door teaching issue. Of course I will obey. I might disagree, but the UHJ has the authority to do that.