A modification of the physical laws should be attempted when all classical hypotheses lead the wrong way. However, such modifications are not uncommon in Physics. In particular, in Astrophysics, we could remember the so called Steady-State Cosmology, which added a term of matter creation. MOND is particularly attractive because, with a single adjustable parameter, and a very limited range of allowable values, it is able to explain the basic facts of galactic dynamics very satisfactorily.
Equations (96) and (109) are not as simple as Newton's equation. Simplicity, beauty and symmetry are apparently non-scientific aesthetic concepts, but have often inspired scientific discoveries and should not be completely absent when a renewal of the fundamental laws in Physics is proposed. Indeed, simplicity is an ingredient in MOND. Equation (95), for example, was proposed by Milgrom because of its simplicity. Nevertheless, MOND equations could be not simple but nevertheless true.
However, Newtonian Dynamics, irrespective of its historic origin, is at present an approximation deduced from General Relativity and therefore it enjoys the protection afforded by this wholly accepted theory. So, proposing corrections to Newtonian Dynamics means rejecting General Relativity, one of the most perfect physical theories. Unless MOND acquires a similar justification by General Relativity, it would remain difficult to be accepted, and to date no such derivation has been reported (Sanders, 1998). For such a task, the modification of Einstein's Field Equations would be more acceptable than a reformulation of the full theory of Relativity.