Personally I completely disagree with the in game purchase system. it's no better than gambling, slot machines and should be banned for games such as this. They should sell the game at a price and allow for progress through skill and effort. An opinion I doubt many here would share and unfortunately it's on the increase.
This is why people who complain about paying a subscription fee for high end games should give it a rest. The subscription based larger games are the best ones out there.
They are far more fair. And the content is generally better.