I know a lot of people dont understand that change.
Let me tell you why private mines are OP.
Since there are a lot of bonus you can get by crafting, it means hardcore players will have to craft a lot of guns,ca, helmets, etc. in order to get the best items possible. Now, it's really easy to do so by buying tons of mines and using alts slavers to drop 3-4 slaves there for a week and go back to doing other things. That means there are no effort (or very few) given into collecting the things necessary for those huge amount of craft pvp players need.
Now, that said, it's so easy to buy mines and collect 10k+ of everything without working and being after able to craft thousands of stuff that PVE becomes useless. Why go and farm CA or guns when you can craft special ones with few effort?
I personnaly have thousands of items, not because I have OCD trouble, but because I use only the very best of the best (advanced, unique, etc.) So regular stuff I rarely use. Why would I?
Also, you may not know, but crafting to up level is very easy. For example, last week I upped one of my newly made char to level 1 to level 79 in ~2 hours of crafting.
Makes it too easy!
Those are a few reasons. Now, casual players will always lose in term of beneficial, since IN ANY GAME, hardcore gamers will dictate the way the game is adjusting.