Oh I don't think visiting famous or well-visited "attractions" makes you "terminally unimaginative" - I hope not anyway. Nor does it mean that, as a visitor to well-visited places, you can't also visit other, less popular sites or that your enjoyment of either will be diminished.
If I travel from Australia to Delhi, for instance, and really want to see the Taj Mahal, then I need to prepare myself that to do so will involve sharing the experience with a lot of others, queuing etc. Otherwise, I don't see it, even though I may see other, less popular sites where I can spend more time. It is a choice you make, and a rather indulgent one at that, whichever way you choose.
As for "experience", well I feel that there is an experience to be gained, even if you are rushed. It is, after all, how people currently view such sites and so it is the contemporary experience of the Acropolis or whatever. But it is more than that. To some extent, and as an aside this is true of photography, when we focus on something (an "attraction", a model, a scene or whatever) we all have the ability to a greater or lesser extent to screen out the noise surrounding us. If the desire to "experience" the thing is sufficient to overcome the negatives of the overcrowding situation, then we are potentially a little richer, surely.
But, point taken - there are few things better than to visit someplace that you have come a long way to see, or really want to see/experience, and to have the experience to yourself or with just a few others around.
