I don't see either "dominating" the market, but both sharing the majority of the market. However, Android has an "in" with allowing several device manufacturers to use their platform.
I could see Android taking a larger share of the market but it wouldn't be domination. Considering that android has about 26% of the smartphone market to iOS at 25%, android is already surpasing IOS. I would say that android isn't as far behind in the developement phase. Android was released a year after iOS first showed up and that's a big jump in the electronics market (particularly in cellphones at the time).
Given that they are on basically the same starting point for tablets, i'd expect that android will be more popular. Less people to convert. Not only that but having several manufactures involved will result in Android having a larger range of devices to choose from. Much like the smartphone market, getting an android unit can be a lot cheaper than getting an iphone. Competition will drive down prices more with Android.