1. to late for that.
2. the game is becoming more casual and new people friendly.
3. in my opinion the situation of the mats in csnm is good since not everyone wants to do the hardest dungeon but still people want it for the rest of the dungeons.
4.making +15 is hard enough and not everyone can do it, and you want to take another small boost? for real?
5.I don't find cshm fun, especially if you need to look for random people and lfg, so this dungeon being optional is good idea.