Francis,
Robert Wright's warning is a really good one. Basically after a certain point in meditation, it really does become about dropping defense mechanisms (in the psychological sense) and purification. A lot of our old ways of thinking/coping become blatently obvious and seen as childish, and in its place is not a new stability, but rather an ability to navigate in a world of ambiguity. If folks are really comfortable in their life, then short meditations as a sort of adult "quiet time" is probably fine... but if you increase the dose with meditation retreats or serious daily practice, then things _will_ change.
One thing that seems clear to me in retrospect, is so much of our habits and behaviors are kind of wired into our body. As a result, when we start turning over rocks in our psyche, it is a full mind-body process and it feels a bit like a slow-speed drug detox.
Now that said, if you go through it all, then it is very easy to say "good riddance" to all those defense mechanisms and it is very easy to prefer the results of meditation... but it is a lot like saying I just spend 7 years going to the gym everyday and my body is stronger and healthier --- well it should be with all that effort!
So yes, anything more than short recreational meditation should come with a warning label. It can be disruptive and difficult. It definitely makes you both more sensitive and resilient, but you have to go through phases where it is quite difficult -- old stable perspectives are falling apart and no new comforting perspectives take their place, except for a very adult (and paradoxical) sense that "meditation gives you stability by becoming aquainted with instability".
Just a few other cautions:
* People have lots of horror stories and glamour stories of what meditation does (you find no self, you find true self, you have no agency, you're on autopilot, you are empowered) -- my experience is while there are states that suggest these have an element of truth, in the end there is an appreciation that these are simply states that people cling to. It's much more accurite to say everything becomes an honest "middle path" between extremes states of self and no self, intention and no agency... etc. etc.
* People have a lot of ideas about what philosophies someone who has gone through the whole deal would have (vegan, omnivoire, pacifist, warrior, meek, wrathful, etc. etc.) -- my experience is while all of these are valid views in their own way, again in the end there is a lot more appreciation for both their true and falseness and living life becomes -- rather that living out a particular philosophy -- much more of navigating life on a case by case, moment by moment basis. Again, very middle path when it comes to views.
* There are many people (myself included) who started meditation in part as a way to get away from the shadow part of their psyche --- these people often have an idealized version of what meditation is and does... and it can be a harsh wake-up call when meditation gives them a much more complex insights and results.
* Ultimately, meditation will point out our very very very basic sense of "woundedness and lack" and shine a big spotlight on it. It will never heal that wound or fill that lack, but rather point out how we were confused in the first place about being wounded and lacking. It's a very strange process to describe, but by going deep into how we relate to the world as self and object, interior and exterior, we eventually see that there is a very basic coping mechanism of trying to put the world "over there" so it can't really hurt us, and me "over here" so I'm in control. The end result is the boundaries become much more porous and flip-floppy and there is a greater clarity and intimacy with what is experienced. It is a bit like waking up from a dream, waking up to the obvious.
To wrap it up, I was personally compelled to really do the work and "get" what this was all about. It was basically something that haunted me my whole life. I don't push meditation on my wife, family, or friends. It's not essential for a pretty good life, especially if the person is trying to be a good person and create a good society for everyone. That said, yes there is something deep in this stuff that people who do not do the practice will miss out on, they will not have the same deep sense of "knowing oneself" as a meditator. But maybe that's no big deal. My hunch is that when people reach their developmental limit and feel the stagnation, then they are probably ready for it and will hunger for a meditation practice.