By your compare, maybe not much. But compared to what was in the MediaVP's, a lot.
Instances of .rgb at the end being gone as a supposed fix: undone.
There are also a lot of consistency fixes in several files even in ma_shaders. In two or three cases, specLight= between some files was completely different.
vec3 halfV = normalize(halfVec) was pulled because in many files, halfV was only used once when it could have been used twice, though in some cases it was used three times instead of normalize(lightVec) being used to float diffuseLight (and I don't mean the float dotV). Speaking of which, vec3 lightVecNormalized = normalize(lightVec); was done away with due to A: Inconsistent usage and B: it really is not any shorter. lVecN would have been good, short and fast, but frankly, after setting the two above to long form, I did not notice either a rendering or FPS change that merited one over the other, So in the case where each is only used once, why make more text? Over all, it saves file space doing them this way.
The re-order took place because, while I can post no argument against whether it _should_ have any effect, the results says that it _does_ have an effect. At one point the bump sections got placed above ENV to make them work right. Given that many of them were using c_env = textureCube(sEnvmap, envReflect+(c_bump * lightVecNormalized)).rgb; and the lightVecNormalized was placed after the bump, it had no chance working where it was. c_env = textureCube(sEnvmap, envReflect).rgb; is the right way of doing it, but the move was already made, so I just laid it out logically: Normal Map is the detailing to the physical lines over which the base (diffuse) map is painted over. It sounds strange, but it seems to be the perceptive case that it does do something.
While many of what is detailed above was largely already present in the ma_shaders, they were not in the mediavp shaders, so try comparing those two some time. Even compared to what was supposed to be the final version for the patch shows a lot of changes.
And for all else, it was a training exercise in load the -v, fiddle with related -f's, don't break anything, and then make sure every thing works. So far it does. If you don't notice any difference in their use given what I know I have changed, then they are doing their job.
Now to see what falcon2105 says.