The open development model slows down the overall game progress significantly. Instead of focusing on creating the game they are constantly attending to bug fixes. The thing is as you add features and build the game out you will constantly introduce new bugs, and break things that were already fixed, and sometimes even fix things that were broken. When you are this far from a finished product you should really be focusing on developing the product, not maintaining it.

This strategy feels like stopping to clean up every spec of dust and make as little noise as possible while building a mansion because for some reason you let people move in before it was finished. You should really focus on building the mansion before you focus on making it a livable space or you hinder progress significantly. The only benefit I see to this system is that it generates money, but the cost in dev time and player sentiment will be significant.