The curious thing is the trouble spots have been mapped. There are filaments and voids where the gravitational effects of unseen matter/stuff are plainly observable: something is there pulling on stuff. MOND is not enough to answer that.
I'm not saying that MOND is correct at all, I'm saying that we believed that classical Newtonian dynamics was seen as correct at one point - just like SR is seen as correct now. My opinion is that it's highly unlikely that SR is incorrect (or partially incorrect), however, I do see it as a remote possibility.
> There are filaments and voids where the gravitational effects of unseen matter/stuff are plainly observable
Another way of looking at it is a map of the sum of things that we don't know. Again, using Mercury as an example, we were able to calculate the [sum of] force the was "wrong."
The dark matter map is incredibly cool because it's the same thing done on a unbelievably massive scale. There were certainly people who believed that this unaccounted-for force on Mercury was a single force with a trivial explanation. We now know that this was not the case.
That is, in my opinion, the same mistake we are now making - simply because we can calculate a map of the effect does not mean that it's actually a map of real stuff.
Although I'm in disagreement with MOND I do think it does something right: the μ function. "This is something that we don't know." In the same way it is in my opinion that dark matter and dark energy are merely unknown functions and not "real matter" and "real energy." I certainly think that Turner and Zwicky had the same thought pattern when they coined the terms.
MOND is quite interesting indeed (been to a couple of Mordechai lectures about this subject), the only problem is that it can't be used to construct a functional universe under TeVeS stable stars couldn't form.
Sadly Jacob Bekenstein died just a month ago and I'm not sure how much work will be done on MOND now.
