Unfortunately it also automatically pushes out updates from mod authors who aren't under any obligation not to make breaking changes...
Is it not similar to how it work for any official update from soase... with each new patch, it invalidate previous savegame... why will modders have a obligation that game dev don't respect...
To my knowledge, with soase, when a mod break a game, it is usually because it upgrade from one version of sins to the other...
By the way, in the case of soase, simply adding a mod version number for the main directory name resolve problem... by example, you can have a structure like :
- Mods-Entrenchment v1.052
-- mymod v1.02
-- mymod v1.03
- Mods-Entrenchment v1.053
-- mymod v2.0
Well, it am not sure that the steam mod thing will be able to handle the complex soase structure for mod directories...
By the way, in some case, modders need to make breaking changes for reach the desired effect... for example, i have made long time ago a skin job for Dragon age origins... it was impossible to reach the desired effect in game with playing on the tint parameter... so, for my little mod, you need to run a config tool before begin play for setup a body not shared with other character in game and create a fully new character else the head will be flooting over the body... final result was great, and the more important, the new character was not reversing to basic character in the cinematic scene :