Data means nothing without the ability to get meaningful information from it.
I still see a lot of discussions around pure data everyday, most of them completely pointless.
“I am sure this works, data says it clearly!”. False, data is raw. Data says nothing. Data has to be put in context.
“You think our players would like this? Let’s prove it with data!”. You will never prove anything with data, you should write down concrete hypotheses and then take the raw data and transform it first in information and, only after, in insight.
“Yes, I also like this. But I want to see the data first!”. If you want to make real games you should consider just being bold sometimes. If you really like something, put it on! Players will appreciate that. If results are bad, I swear, it will probably depend on other things.
If you use the data-driven approach, you risk to really miss your point because when anything becomes the subject of our analysis the result of this analysis will be influenced by this fact. You should use data to get information to inform your design decisions, not to drive them.