I'd agree that most cone design and construction is far advanced these days. A good designer can use the driver of his/her choice and produce a world class speaker if talented and with the right budget.
I've not really been concerned about cone types in the dynamic coned boxed speakers I've had over the years. The sound produced was the first concern. That said, over time I realized I like soft domes, silk, etc, far more than metal-domed or diamond tweeters. Some are good but still too tiring, so I shy away and now I love the sealed ribbon tweeters I have more than anything else.
I laugh at those who disparage paper cones. Please understand and believe that 'this paper isn't the same paper of years past'. That is for sure. :-) Again, a great designer can do a lot...