Wild Cards have been a bit of a mixed bag in Minion Masters — allowing for both inventive gameplay and abuse. So, the developers have decided a rework is in order. Basically, they’re trying to add more balance to the mechanic, still giving players the opportunity to use them in play, but making them less of a full strategy and more of an addition.
These cards will now only be made available as the 11th and 12th card in a deck. This means players will need 10 unique cards in a deck before they can begin playing. The idea is that this will create some downsides to having Wild Cards in a deck — slowing things down a bit due to having to cycle through cards.
The developers decided that a good way to test this new system out is to simply include it as part of the version 1.12 update on the live server. They’ll be leaving it there until the next patch. Normally, this kind of thing would be done on the PTR, but by adding it to the live server, they are able to guarantee a bigger test pool.
If you’d like to read more about the thinking behind this change and how it’s being implemented, the BetaDwarf blog has a detailed post for you. It even includes answers as to why some things they considered weren’t done.