It's no win scenario for developers. While you're ok with "one up front payment and then maybe in app purchases to pay for new features going forward" there's a whole other slew of voices who are going to complain about being nickled and dimed.

Given those choices (and other factors), as a consumer I prefer the subscription model. If nothing else, it lets me forecast my expenditure and continually re-assess the cost/value proposition of the application in question.