blizzard is still actually making more money from wow every year than every previous year, so while sub numbers are way off the peaks they are still managing to keep a high western audience mix and apparently get a lot more money from cash shop and people just buying all the xpac boxes. If their subs dip from 9m to 7m over one year, that doesn't just mean they "lost" 2m subs - they may have lost 4m players, but also gained 2m new players who all bought wow+xpacs+3 month gamecards, which is a lot more money.
Their growth rate ($$ wise) has stalled a lot however, and for a public company how much you grow your revenue and income every quarter and every year is more important than how much you make.
After Kotick finishes his buyout of Vivendi, Blizzard will undergo even more severe pressure to grow the business and you will probably see a big exodus of talent, especially with Titan pushed so far out now.