It wouldn't be based too much on user complaints or metacritic scores for SimCity or any other game really. Underperforming revenue is likely the largest factor in Riccitello's departure. There has been a string of quarters hitting below/low on their outlook.

To Riccitello's credit, EA was in a terrible position pre-recession. A bad business plan, an inflated stock price and a bloated portfolio. JR had to make some brutal choices during the recession and has turned EA into a leaner beast, banking on online distribution and focusing on a smaller, higher quality portfolio.

And while the big picture of where he took EA is a logical one, I assume that the missed revenue from underperforming titles is the biggest factor in him stepping down. Of course, this is all conjecture on my part.