MTS tax - good or bad thing?

They probably thought more people would go out and buy NX from the store since it's harder to make in MTS.

Thing is, every single cent in the MTS already came from NX. Making the MTS less useful cuts both ways - people use it less, so the people who were injecting NX into it have less incentive to do so (less items available, especially the cheap ones where it's like "whatever, 20 cents for a quest"), but the people who used it to make NX can't. All it leaves are the crazy people willing to spend $200 on a virtual item... and that is less common than the one who charged 10 bucks, had 800 NX left after buying their pet, and just wants to use it.