Hey
I'll try to answer but at the same time the changes around classes/feats/spells were all made by DMs/Devs that are no longer active quite a few years ago so can't directly answer (and I am not sure they would see this to answer themselves).
Background - I voluntarily stepped in about 3.5 years ago after the server went offline for a six month period in an attempt to get it up and running again, as there was still a fair amount of interest in terms of the player base. The DM/Dev presence on the other hand did start to suffer around that time (which is why it went offline for so long probably). But after getting in touch with the last of those Devs including Turril who was hosting it back then, and Terrorble who was able to provide me with an up-to-date version of the mod at the time, GreyDeth and myself were able to get things up and running again.
Generally speaking the updates I have made in those 3.5 years have mostly been around bug fixes, new areas and introducing a few things to make things a little easier (e.g. perma haste, travelling, alignment restrictions lifted to name a few).
As I say the classes/feats/spells changes were all done years ago by now inactive devs, but I think the rationale behind it was to try make everything useful or viable as the mod is a hard mod.
So for example picking a spell at random of ice Dagger - before the changes serves little or no purpose to builds at level 10 or what ever. But now it is a useful spell to have in a level 40s arsenal which opens up a whole load of new options and not just relying on the usual attack spells that only worked before the changes (horrid and the issacs to name a couple).
The same can be said for the classes, all the shifter changes allows for a whole load of new possibilities where before most of them were pretty redundant outside of dragon and maybe the old stone golum.
I am not sure if you were around when the vault wipe happened and all items got toned down? That was several years ago now. So the magic all got reduced back then too.
Hope this helps
-fc-