Personally, I think that playing behind the beat is just part of playing and don't usually give too much thought about it.
BUT (and you knew that was coming, right?
I also think that a lot of beginners (or, if you prefer, people taking their first steps in soloing) tend to make their solos very even in terms of rhythm and dynamics. To be fair, that's usually how one starts to make the move from playing scales to playing solos. So the concept of being able to play behind the beat or to use rhythm as a textural soloing tool is good for someone to develop and while a lot of people can hear it, they can't always play it.
And I hope to heaven you know that I'm not talking about you in this case! Having heard quite a few examples of your playing, I think that you have a good command of phrasing and that this isn't something you need worry about in the least. As you noted, it's a lot like your other blues improvs, which I've enjoyed immensely, by the way.
I'm not really sure why it was originally that big of a deal in the first place, either. But then again, I'm usually the last to know what's going on!