You literally get on me for using opinion and you start you response with an opinion. There is no "more correct" definition of flop. A flop is generally considered to not met expectations due to poor quality given. A financial or commercial flop is used to describe something that failed to meet expectations for a reason other than poor quality. Neither is "more correct." When you call something a flop you are making a judgement the quality of the product was poor (SW:Tor wasn't a poor product, just underwhelming which is different).
And you are right about about WoW, it won't go F2P it has no reason to at this time. I would say it goes F2P if and only if it drops below 1.5 million subs.