It seems like in a business-driven organization (i.e. where the sales and marketing team has a bigger say) that offer software products or services, A/B testing is used as a way to improve and measure 'UX'. I have looked at many of the websites that offer this service and more often than not they simply reveal practices that seem contrary to good user interface design practices, and therefore changes to the design appear to provide the boost in conversion rate. On the other hand, there is a school of thought that failing quickly so you can make changes seem to make sense in an 'AGILE' software development environment.
I believe that A/B and multi-variate testing as it stands covers only a small part of the UX design, and that there is too much weight given to the conversion process. However, it seems that many companies prefer to do this type of evaluation compared to a proper study of users and a user-centric approach to product development.
What are the parts of UX design that can be incorporated into A/B and multi-variate testing to cover not just the business related goals, but also the customer/user experience improvements?