I agree with your top 4, but I'm going to make the case for Calvin over Miggy:
1) The Lions are more popular than the Tigers, despite being historically much worse. If the Lions make a run for the division title this year (which looks completely possible) and Calvin is dominating week in and week out, his popularity in Detroit is going to go sky high.
2) Miggy isn't the most likeable person. He's had his fair share of issues with the drinking and the domestic violence reports. Heck, he barely speaks English. A few years back when his issues were more prevalent, there were some Tigers fans who wanted to run him out of town. Not taking anything away from his dominance at the plate or the smile on his face when he plays the game, but off the field, no one knows much about him because he's not the most open person. I think more Tigers fans relate to Justin Verlander, who is American and does a lot of stuff in the community. Likewise, Calvin appears to be a great human being even though he has a quiet demeanor... Calvin is more marketable and approachable to the fans.
3) Calvin is more valuable to the Lions than Miggy is to the Tigers (which sounds nuts). But if you take Miggy off the Tigers, they can still compete with pitching and they have a few other bats. But you take Calvin off the Lions and they don't have a chance.