The CMA in the UK is still trying to block it. Appeal is in two weeks. That said, even if they were successful I get the feeling that MS would just do a business carve out in the UK and acquire ActiBlizz anyway
Based on my (admittedly limited) understanding of the situation, you're right. Microsoft have already hinted that if the UK interferes with the deal, theyd stop doing business there rather than pull out of the acquisition.
Only when it actually goes through, and companies are very, very careful to not intermingle during an ongoing merger as that leads to problems that kill mergers