The 7000 year long creative day argument has not been 100% fully rejected. What they have said is that the creative days could be many 1000s of years long, allowing for a time range from their old doctrine right up to the 4.6 billion years that science suggests. They are not so dogmatic about 7000 years but they've not said anything that puts the idea completely to bed.
Of course, most modern day Witnesses just go with the science as it's less controversial however there are still ones around who think of far shorter timescales, some still thinking the dinosaurs were around with Noah. I know - some of them are in my congregation....
The current WT stance allows them to be pedantic about suggesting they agree with the scientific community without ever really distancing themselves from a position that weakens their secular credibility, It's doublespeak just like their silly statements about creationism.