I have W/P 6s and have listened to the 7s at shows and dealers.
The 6s' weakest points (in my opinion) are that the tweeter is a little hot and the puppies have a little midbass prominence but don't go all the way down. The hot tweeter is usually addressed by adjusting toe-in -- the speaker is fairly sensitive to placement. The side benefit is that people who like sharp, analytical speakers can get what they like here. I find that I like the small midbass prominence, as you noted, too. I am supplementing the puppies with two subwoofers, so the 6s' lack of very low bass is not an issue with my set up.
The 7s use an improved enclosure material, which I have read permits some tweaking of the crossover to smooth out the tweeter. Apparently, this also supports other changes in the crossover and puppy driver systems to smooth out the midbass prominence and extend the low end. The result seems to be a flatter and more extended speaker frequency response. The speaker is less sensitive to placement, and perhaps a little more forgiving of upstream components. To me, the sound is a little less intense as an experience. To exaggerate for illustration, the sound is a little less "West Coast" and a little more Boston. Relative to other speakers I listened to, the W/P 7s are still colorful and dynamic (just not quite so much as the 6s). These attributes, plus the beautiful fit & finish and high efficiency (especially if you are thinking about tube amplification), keep the design attractive. Whether it costs too much is up to your personal wallet.
The 6s' weakest points (in my opinion) are that the tweeter is a little hot and the puppies have a little midbass prominence but don't go all the way down. The hot tweeter is usually addressed by adjusting toe-in -- the speaker is fairly sensitive to placement. The side benefit is that people who like sharp, analytical speakers can get what they like here. I find that I like the small midbass prominence, as you noted, too. I am supplementing the puppies with two subwoofers, so the 6s' lack of very low bass is not an issue with my set up.
The 7s use an improved enclosure material, which I have read permits some tweaking of the crossover to smooth out the tweeter. Apparently, this also supports other changes in the crossover and puppy driver systems to smooth out the midbass prominence and extend the low end. The result seems to be a flatter and more extended speaker frequency response. The speaker is less sensitive to placement, and perhaps a little more forgiving of upstream components. To me, the sound is a little less intense as an experience. To exaggerate for illustration, the sound is a little less "West Coast" and a little more Boston. Relative to other speakers I listened to, the W/P 7s are still colorful and dynamic (just not quite so much as the 6s). These attributes, plus the beautiful fit & finish and high efficiency (especially if you are thinking about tube amplification), keep the design attractive. Whether it costs too much is up to your personal wallet.