Hmmm...
Oooh!
We do!
Plagiarism!
I can't agree with OP's view here. It's textbook plagiarism. The opinions and sentence structures are too similar. Changing a few words to obfuscate the fact the content was stolen does not stop this from being plagiarism.
If I had an assignment to write about a book but I'd not read the book, I could take an essay about that book from the internet and change a few words and rearrange a few sentences to pass it off as my own. I'd then get pinged for plagiarism, rightly. At my university, plagiarism was not accepted and I'd have been ejected from the course. I'm not saying Miucin didn't play Dead Cells but he certainly failed to formulate and articulate his own content. If I use or paraphrase content, I'd cite the original owner of that content. If I don't, it's plagiarism.
IGN were right to fire him too, even if Boomstick Gaming didn't want that outcome. They may feel they must compensate Boomstick Gaming because of this incident. If they'd kept Miucin on, every single one of his future videos would have been trolled to hell. Because internet. IGN won't tolerate that for a clear cut case of plagiarism - it'd be terrible for their brand.
If Boomstick Gaming gets a higher viewership from this, so be it. He didn't ask for his work to be stolen.
If Miucin can't get another writing job, that sucks for him, and I'm sure he'll be full of regret. Unfortunately the internet doesn't easily forget.