I don't think that microtransactions are wrong, per se, but I do generally find it to be in bad taste. But that's an art versus entertainment question and the vast majority of the industry (and its customer base) have landed very firmly on "entertainment" which leads fairly inevitably to caring about nothing except profit.
"We're building into all of our games the ability to pay for things along the way." [1]
This kind of thinking from the games industry concerns me. If I've paid full price for a game, I don't think I should be nickel and dimed for more content.
[1] http://www.gamasutra.com/view/news/187421/EA_details_microtr...