I see where you're coming from with some of the prophetic gifts and interpretable tongues or interpretation of such tongues. But, being raised around many of them, it seems that personal use of tongues for edification of oneself and a special language used in prayer tends to be a constant gift for most people.
I've also seen people who use it who make no sense whatsoever, but claim it to be a gift.
Considering its purpose, to help the new believer express his/her prayers in a Godly manner, to give you words to pray when you don't know what to say... it seems this particular gift is usually constant; and, having it, I thank God it is. I don't know what I'd do without it.
Paul really did not seem to be much into speaking in tongues. In fact, it almost seems like he merely tolerated it, and to be encouraging and/or not really slap down people who insisted it was a valid gift, he instead said, "Well, it is more important to focus on the ability to interpret tongues, not just speak in them. But really, if you've got to choose... love each other and drop the whole silly tongue business." His most famous declaration about love, the core of relationships with every other human being, occurs in the middle of telling people to stop arguing about how great the gift of tongues is.
Honestly, if I were God, I would rather hear you stammer and stumble and get stuck and be confused about what you were saying... and try to talk to me anyway and understand what you were saying, rather than just talking to myself through you. That would show how much you love me, and how much humility you have (because you're doing something uncomfortable but your image is less important to you than your prayers), and so on.
As for gifts of discernment, those I've seen (quite a few) who had them, also had them constantly, even when they themselves weren't doing quite right and were running from them. I consider this particular gift to be almost like a special, well, I guess you could say, a sixth sense of sorts. Once you have it, you usually develop it and never lose it. It's just like with natural sight, once we have it, we have it (unless something goes wrong). Once it's there, it's meant to stay.
I just don't know. You have no doubt seen many of those spiritual gift tests all around the Internet. (Someone had even had a test along with the MBTI and a skills test, but he took it off when people complained... from what I heard.)
I always get discernment, teaching, wisdom, and exhortation/pastoral as my very highest. And other people confirm those things informally, when I give them advice or talk to them about particular situations. They will just volunteer the compliment, so it's not just me imagining all that.
So what does that mean? Is that even the same as the gifts you're talking about? It seems to me there is this very ambiguous area and we are just making things up as we go, but we really don't know what a gift is or how it appears or why or when it is even being used. We just validate it based on how we "feel" about it and whether the results seem to mesh with what we already think and have been taught.
I'm glad you pointed out earlier (I think I saw you say it!

) that the gift of prophecy was not just about foretelling the future but actually just declaring the will of God in a particular situation. That is an important qualification many people don't understand at first...
Because they are gifts, God is not going to spring them on someone who will not receive them. So, it is not the fault of the gifts that this partial distribution is true; it's the fact the so many don't believe in them and don't want them. Paul told us to seek the gifts; and, as far as I know from personal experience, people who don't seek them usually don't receive them.
I understand why you're saying this. But you probably also see why, as far as inquiry goes into the authenticity of the gifts by an outside observer, it's very much a self-fulfilling prophecy. ("Those other people don't receive the gifts because they don't really want them like we do." The counter-logic: "You think you're receiving gifts, because you've convinced yourselves you are.")
Sure, this probably does occur, but the gifts I have seen in operation are undeniable.
I think there are some things that are unexplained or ambiguous, but "undeniable" is far too strong a word. It's not as if I have not been exposed to deliverance meetings or large spirit-oriented worship sessions or seen "healings" on television or spoken with people who have had things occur that they deemed to be miracles. And I have a few incidents in my own life to me that seemed at the time to be inexplicable.
But I cannot make a systematic theology out of it. It's "gray area" to me. And I am also very very aware of bias in Christian perception, in both my own life and in the lives of people I know intimately. I am very aware about how operating from a worldview based on revelation often leads us to immediately categorize our experiences in terms of that worldview, rather than being aware of other possibilities for that worldview.
Christianity is not the only faith that has had mystical experiences.
For example, one time, I was going through a struggle with a certain struggle that I had only told my (at the time) boyfriend (whom I would later marry) about. Our assistant pastor at the time had so many legitimate gifts that we used to joke about it and say he "knew what we [or anyone else] did last summer" got up sometime after the worship and starting speaking my exact situation and admonishing me on what to do. It was so powerful, all I could do was sit, put my face down on the back of the pew in front of me, and cry.
I know. And I know it felt very powerful to you. I have no experience with your experiences, you are really the only witness to what you are experiencing. I just know what my own experiences have been, and what things "feel real" but later turn out to be more ambiguous, and so on. And I've watched those around me having "religious experiences" and later discover that their convictions and interpretations were not the only explanation.
Religious experiences are very difficult to examine from the outside, because so much of them are subjective and internal.