We've known since the earliest days of the game that the reel when you spin out crystals over-represented high value results relative to their actual drop rates, but we still see people (who should know better) talking about how they "just missed" something. I decided to gather some data so the hard-core spinners could know exactly how skewed the spinner is and better understand the psychological pressure kabam is putting on them to buy just... one... more. So I spun out 101 PHCs and made a spreadsheet.
This could have been better if I'd recorded video so I could look at the last few spots in the reel, because it felt like there was a high percentage of 4* rollovers just before the final three locked in. But there's only so much effort I'm willing to put into this. Just pop them.
Long story short, the left champ in the final three will ALWAYS be a 2*. The right champ is almost ten times more likely to show a 4* than you are to actually get a 4* based on published drop rates and including the nexus. I'm not going to repeat this for grandmaster or cav crystals, but I think it's fair to assume the trend would hold.