Although there are many ways to put -1/-1 counters on creatures, Im considering only MTG cards that put -1/-1 counters on creatures (or on themselves) via their own card text
Number 25 Language English Not Legal Formats Alchemy, Brawl, Commander, Competitive Brawl, Historic, Legacy, Modern, Pauper, Pioneer, Standard, Timeless, Vintage
Since the beginning of Magic, it has remained consistent that you can only tap untapped permanents and untap tapped ones
Changeling Outcast has great synergy with our Orc Army as counts as an Orc Army too, so we get an unblackable Orc Army that we can easily buff to be a finisher
This all adds up to making this a lot lot better than Introduction to Prophecy, even if it is still a little bit underwhelming